JP3680518B2 - Rotating body driving apparatus and image forming apparatus - Google Patents

Description

【００１１】
であらわされるとすると、慣性モーメントＩを大きくすることにより、固有振動数ｆの値を小さくすることに相当する。
【００１２】
一方で、駆動系の途中に弾性部材を設けることによって駆動精度の向上をはかることは、駆動系で発生する回転方向の振動成分を弾性部材内で熱に変換し、散逸させるものである。ここには駆動系の周波数特性や伝達関数といった概念が入っていないので、発生する振動の加振周波数や駆動系の構成によりその効果が予測できず、効果のレベルもまちまちであった。
【００１３】
特願平９−７４８４９号明細書においては、固有振動数と伝達ゲインのコントロールが容易に可能であるが、粘弾性部材の損失係数を大きくし、共振ゲインを下げると、振動減衰域のゲインが上がり、防振特性が低下する問題がある。更に、負荷条件や、ラインスピードが変化した場合、加振周波数や固有振動数が変化し最適な防振特性が得られない場合がある。
【００１４】
【発明が解決しようとする課題】
デジタル方式の画像形成装置の開発では、性能が向上するに従って、レーザ書き込みによる１ドットラインの再現性が厳密に求められ、駆動系に要求される精度も急速に厳しいものになった。ここで要求される精度は、レーザによる書き込みの副走査方向の均一性が視覚系の可視感度との関係で保証されるレベルであり、記録密度が６００ｄｐｉから２４００ｄｐｉといった高密度記録化に伴って、スモールピッチバンディングが人間に認識できない高レベルを満足する高精度の回転ムラのない回転体の駆動が要求される。
【００１５】
このため、従来技術の範囲においては、回転体の駆動の高精度化には高精度歯車や、駆動の専用化、大型のフライホイールの採用などが一般に行われている。しかしフライホイールの採用は既に述べたように重量や装置が大きくなることは避けられない。更に電子写真方式のプリンターを提供する為にも、軽量、コンパクト、低コストで高精度な駆動を構成するという要求の為に、歯車駆動力を弾性部材を介して感光体ドラム等の回転体に伝達する構造等が提案されている。ところがこの技術においては、弾性部材のみでは、固有振動数以上の速度ムラ低減効果は大きいが、共振領域のゲインが大きくなり、共振領域近傍の速度ムラや、負荷変動の影響を大きく受け、バンディングが悪化する問題があった。
【００１６】
本発明は、それらの問題を解決する新しい構造により、軽量、コンパクト、低コストで、外乱等による影響を受けにくく、高精度な駆動が達成することにより、高画質の画像出力を可能とする回転体の駆動装置、及び画像形成装置の提供を目的とする。
【００１７】
特願平９−７４８４９号明細書においては、これらを解決すべく提案がなされているが、共振ゲインを下げるために、粘弾性部材の損失係数を上げると振動減衰域のゲインが上がり、防振特性が低下する問題があった。更に、負荷条件や、ラインスピードが変化した場合、加振周波数や固有振動数が変化し最適な防振特性が得られない場合がある。本発明は、それらの問題を解決する新規な構造により、軽量、コンパクト、低コストで、外乱等による影響を受けにくく、感光体ドラムやベルト感光体駆動ローラ等を、高精度に駆動することにより、高画質の画像出力する画像形成装置を提供することを目的とするものである。
【００１８】
【課題を解決するための手段】
上記の目的を達成する本発明の回転体の駆動装置は、回転可能に支持された回転体と、前記回転体を駆動する駆動源と、前記駆動源の回転駆動力を前記回転体に伝達するための駆動部材と、従動部材と、連結手段とを有する回転体の駆動装置において、前記連結手段は駆動連結部材と従動連結部材とから成り、前記駆動連結部材には、弾性変形可能な可撓性梁状部を有する弾性体部材と、前記可撓性梁状部の一面に面接触して固定された流体封入型防振手段とが設けられ、前記従動連結部材は連結用突起部材を有し、前記可撓性梁状部に前記連結用突起部材を当接させて連結させ、前記駆動源の回転駆動力を前記連結手段を介して前記回転体に伝達することを特徴とするものである（請求項１）。
【００１９】
また、上記の目的を達成する本発明の回転体の駆動装置は、回転可能に支持された回転体と、前記回転体を駆動する駆動源と、前記駆動源の回転駆動力を前記回転体に伝達するための駆動部材と、従動部材と、連結手段とから成る伝達手段とを有する回転体の駆動装置において、前記連結手段は駆動連結部材と従動連結部材とから成り、前記駆動連結部材は連結用突起部材から成り、前記従動連結部材には、弾性変形可能な可撓性梁状部を有する弾性体部材と、前記可撓性梁状部の一面に面接触して固定された流体封入型防振手段とが設けられ、前記駆動連結部材の連結用突起部材を前記従動連結部材の前記可撓性梁状部に当接させて連結させ、前記駆動源の回転駆動力を前記連結手段を介して前記回転体に伝達することを特徴とするものである（請求項２）。
【００２０】
上記の目的を達成する本発明の画像形成装置は、少なくとも画像を担持する像担持体と、前記像担持体へ画像を形成する作像手段と、前記像担持体或いは該像担持体を保持する回転体を駆動回転させる駆動源と、前記駆動源の回転駆動力を前記像担持体或いは回転体に伝達するための駆動部材と従動部材と連結手段とから成る伝達手段とを有する画像形成装置において、前記連結手段は駆動連結部材と従動連結部材とから成り、前記駆動連結部材又は従動連結部材には、弾性変形可能な可撓性梁状部を有する弾性体部材と、前記可撓性梁状部の一面に面接触して固定された流体封入型防振手段とが設けられ、前記流体封入型防振手段は、前記可撓性梁状部に当接する側に粘弾性部材と、該粘弾性部材に閉蓋された箱体とを有し、該箱体内には、流体流通用のオリフィスを有する仕切り板と、該仕切り板により仕切られた第１の流体室と第２の流体室と、前記第２の流体室と空気室とを移動可能に仕切る防振ゴム膜部材とを備え、前記流体封入型防振手段の第１の流体室及び第２の流体室内に収容される流体は、電界のオン、オフにより粘度が可逆的に変化する電気粘性流体、又は電界及び磁界の同時印加により流体の剪断応力が変化する電気磁気粘性流体であり、駆動系の負荷条件、ラインスピードの変化に応じて最適な防振特性を得るように制御することを特徴とするものである（請求項７）。
【００２１】
また、上記の目的を達成する本発明の画像形成装置は、回転可能に支持された回転体と、前記回転体を駆動する駆動源と、前記駆動源の回転駆動力を前記回転体に伝達するための駆動部材と従動部材と連結手段とから成る伝達手段とを有する回転体の駆動装置において、前記連結手段は駆動連結部材と従動連結部材とから成り、前記駆動連結部材又は従動連結部材には、弾性変形可能な可撓性梁状部を有する弾性体部材と、前記可撓性梁状部の一面に面接触して固定された流体封入型防振手段とが設けられ、前記流体封入型防振手段は、前記可撓性梁状部に当接する側に粘弾性部材と、該粘弾性部材に閉蓋された箱体とを有し、該箱体内には、流体流通用の複数のオリフィスを有する仕切り板と、該仕切り板により仕切られた第１の流体室と第２の流体室と、前記第２の流体室と空気室とを移動可能に仕切る防振ゴム膜部材と、前記複数の各オリフィスを開閉可能にする複数の開閉弁とを備え、前記駆動連結部材に連結する従動連結部材、又は、前記従動連結部材に連結する駆動連結部材には、突起部材が固設され、前記突起部材を前記可撓性梁状部に当接させて連結させ、前記駆動源の回転駆動力を前記駆動連結部材と従動連結部材とから成る連結手段を介して前記回転体に伝達するとともに、前記開閉弁を開閉可能に作動させる駆動手段と、該駆動手段を制御する制御手段とにより、所定の開閉弁を開閉させて、前記オリフィスを流通する流体量を可変に制御可能にし、駆動系の負荷条件、ラインスピードの変化に応じて最適な防振特性を得るように制御することを特徴とするものである（請求項８）。
【００２２】
【発明の実施の形態】
本発明の実施の形態の説明に先立って、本発明の回転体（感光体ドラム）を装着した画像形成装置の一例であるカラープリンタの構成とその作用を図１の断面構成図によって説明する。
【００２３】
このカラープリンタは、感光体ドラム上に順次形成される各色トナー像を重ね合わせたのち、転写部で記録紙上に１回で転写してカラー画像を形成し、その後、分離手段により像担持体面から剥離する方式のカラー画像形成装置である。
【００２４】
図１において、１０は直径１２０ｍｍの円筒状をなす感光体ドラムで、ＯＰＣ感光体（有機感光体）をドラム基体上に塗布形成したもので、接地されて図示の時計方向に線速１００ｍｍ／ｓｅｃで駆動回転される。１１はスコロトロン帯電器で、感光体ドラム１０周面に対し高電位Ｖ_Hの一様な帯電をグリッド電位Ｖ_Gに電位保持されたグリッドとコロナ放電ワイヤによるコロナ放電によって与えられる。このスコロトロン帯電器１１による帯電に先だって、前プリントまでの感光体の履歴をなくすために発光ダイオード等を用いた帯電前除電器（ＰＣＬ）１２による露光を行って感光体周面の除電をしておく。上記の感光体の履歴とは、先行した画像形成時の帯電、画像露光で作像した感光体上に残留した画像パターンをいい、感光体メモリーとも称す。
【００２５】
感光体ドラム１０への一様帯電ののち、像露光手段１３により画像信号に基づいた像露光が行われる。像露光手段１３は図示しないレーザーダイオードを発光光源とし回転するポリゴンミラー、ｆθレンズ、シリンドリカルレンズを経て反射ミラーにより光路を曲げられ走査がなされるもので、感光体ドラム１０の回転によって潜像が形成される。本実施例では文字部に対して露光を行い、露光部電位Ｖ_Lの方が帯電電位Ｖ_Hよりも低電位となるような反転潜像を形成する。
【００２６】
感光体ドラム１０の周縁には、イエロー（Ｙ），マゼンタ（Ｍ），シアン（Ｃ），黒色（Ｋ）等のトナーとキャリアとから成る二成分現像剤をそれぞれ内蔵した現像器１４Ｙ，１４Ｍ，１４Ｃ，１４Ｋから成る現像装置１４が設けられている。
【００２７】
先ず１色目のイエローの現像が、マグネットを内蔵し現像剤を保持して回転する現像剤担持体（以下、現像スリーブと称す）１４１によって行われる。現像剤はフェライトをコアとしてそのまわりに絶縁性樹脂をコーティングしたキャリアと、ポリエステルを主材料として色に応じた顔料と荷電制御剤、シリカ、酸化チタン等を加えたトナーとからなるもので、現像剤は後述する現像剤層形成手段によって現像スリーブ１４１上に１００〜６００μｍの現像剤層厚に規制されて現像領域へと搬送される。
【００２８】
現像領域における現像スリーブ１４１と感光体ドラム１０との間隙は現像剤層厚よりも大きい０．２〜１．０ｍｍとして、この間にＡＣバイアスＶ_ACとＤＣバイアスＶ_DCが重畳して印加される。ＤＣバイアスＶ_DCと感光体帯電電位Ｖ_H、トナーの帯電は同極性であるため、ＡＣバイアスＶ_ACによってキャリアから離脱するきっかけを与えられたトナーは、正帯電時にはＤＣバイアスＶ_DCより電位の高い感光体帯電電位Ｖ_Hの部分には付着せず、ＤＣバイアスＶ_DCより電位の低い露光部電位Ｖ_L部分に付着し顕像化（反転現像）が行われる。
【００２９】
１色目の顕像化が終った後、２色目のマゼンタの画像形成行程に入り、再びスコロトロン帯電器１１による一様帯電が行われ、２色目の画像データによる潜像が像露光手段１３によって形成される。このとき１色目の画像形成行程で行われたＰＣＬ１２による除電は、１色目の画像部に付着したトナーがまわりの電位の急激な低下により飛び散るため行わない。
【００３０】
再び感光体ドラム１０周面の全面に亘って感光体帯電電位Ｖ_Hに帯電された感光体のうち、１色目の画像のない部分に対しては１色目と同様の潜像がつくられ現像が行われるが、１色目の画像がある部分に対し再び現像を行う部分では、１色目の付着したトナーにより遮光とトナー自身のもつ電荷の影響によって、１色目の露光部電位Ｖ_Lよりも若干高い電位Ｖ_Mの潜像が形成され、ＤＣバイアスＶ_DCと電位Ｖ_Mの電位差に応じた現像が行われる。
【００３１】
３色目のシアン、４色目の黒色についても２色目のマゼンタと同様の画像形成行程が行われ、感光体ドラム１０周面上には４色の顕像が形成される。
【００３２】
上記各現像器１４Ｙ，１４Ｍ，１４Ｃ，１４Ｋに新規の各色トナーを制御して補給するトナー供給装置は、着脱可能な複数のトナーカートリッジ１５（Ｙ，Ｍ，Ｃ，Ｋ）、トナー貯蔵手段１６（Ｙ，Ｍ，Ｃ，Ｋ）、トナー搬送手段１６１（Ｙ，Ｍ，Ｃ，Ｋ）から構成されている。
【００３３】
一方、給紙カセット２０より半月ローラ２１を介して搬出された一枚の転写材（転写紙等）Ｐは、中間給紙ローラ対２２Ａ，２２Ｂを経て、レジストセンサ位置近傍で一旦停止し、転写のタイミングの整った時点で、給紙部のレジストローラ対２３の回転作動により転写域へと給紙される。
【００３４】
転写域においては転写のタイミングに同期して感光体ドラム１０の周面にトナー像を転写するための電圧を印加する転写手段１７が圧接され、給紙された転写材Ｐを挟着して多色像が一括して転写される。
【００３５】
次いで、転写材Ｐは鋸歯電極等の分離手段１８によって除電され、感光体ドラム１０の周面より分離して定着装置２４に搬送され、熱ローラ（上ローラ）２４１と圧着ローラ（下ローラ）２４２の加熱、加圧によってトナーを溶着したのち、排紙ローラ対２５Ａ，２５Ｂ，２５Ｃを経て装置外部の排紙トレイ２６上に排出される。なお、転写手段１７は転写材Ｐの通過後感光体ドラム１０の周面より退避離間して、次なるトナー像の形成に備える。
【００３６】
一方、転写材Ｐを分離した感光体ドラム１０は、クリーニング装置１９のブレード１９１の圧接により残留トナーを除去・清掃され、再びＰＣＬ１２による除電とスコロトロン帯電器１１による帯電を受けて次なる画像形成のプロセスに入る。なお、ブレード１９１は感光体面のクリーニング後、直ちに移動して感光体ドラム１０の周面より退避する。ブレード１９１によってクリーニング装置１９内に掻き落された廃棄トナーは、スクリュー１９２により排出されたのち、図示しない廃トナー回収容器内へ貯留される。
【００３７】
図２（ａ）は感光体ドラム１０と駆動機構３０を示す斜視図である。図２（ｂ）は感光体ドラム１０と駆動機構３０の部分断面図である。
【００３８】
駆動機構３０はパルスモータ等の駆動用モータ（駆動源）Ｍ１とそれに連結した歯車列３１〜３３から成る。歯車列３１〜３３の最終歯車３３は、感光体ドラム１０と同軸上に回転可能に設けた駆動歯車（駆動伝達部材）３４と噛み合っている。
【００３９】
感光体ドラム１０の両端部に取り付けられたフランジ（従動伝達部材）１０１には軸１０３が嵌合している。よって一方のフランジ１０１の端面と前記の駆動歯車３４の側面とは所定の間隔をもって位置していて、駆動歯車３４に設けた連結用弾性体（駆動連結部材）３５と、フランジ１０１により設けた連結用突起部材（従動連結部材）３６によって前記駆動用モータＭ１の駆動力は感光体ドラム１０に伝達される。
【００４０】
図示した実施形態では、軸１０３は画像形成装置の本体に対して固定して支持されていて、駆動歯車３４は図示しないベアリング、例えばオイルレスベアリングを介して軸１０３に嵌合し、感光体ドラム１０に取り付けられたフランジ１０１はベアリング１０２を介して軸１０３に嵌合している。なお、軸１０３を画像形成装置本体に対して回動可能に支持し、感光体ドラム１０を軸１０３に対して固定する構成であっても差し支えない。
【００４１】
図３（ａ）は、感光体ドラム１０と連結手段を示す斜視図である。
【００４２】
図３（ｂ）は、連結用弾性体３５の一実施形態の構造を示す正面図である。
【００４３】
前記連結手段は駆動連結部材と従動連結部材とから成る。前記駆動連結部材は、弾性変形可能な両端支持梁部（可撓性梁状部）３５１を有する弾性体部材３５と、前記両端支持梁部３５１の一面に面接触して固定された流体封入型防振手段３７とが設けられている。前記従動連結部材は連結用突起部材３６から成り、両端支持梁部３５１に連結用突起部材３６を当接させて連結させ、駆動源Ｍ１の回転駆動力を駆動連結部材と従動連結部材とから成る連結手段を介して感光体ドラム１０のフランジ１０１に伝達する
駆動歯車３４と感光体ドラム１０のフランジ１０１との間で駆動伝達を行う弾性体部材３５には、両端支持梁部３５１を有した連結用弾性体３５１が駆動歯車３４の端面に設けられ、両端支持梁部３５１が駆動歯車３４のほぼ半径方向となる位置関係に固設されている。フランジ１０１の端面には、棒状で剛体の連結用突起部材３６が固設されている。そして組み立てられた状態においては、図３（ｂ）に示すように連結用突起部材３６は連結用弾性体３５の両端支持梁部３５１のほぼ中央位置に当接し、駆動歯車３４の回転に伴って連結用突起部材３６は両端支持梁部３５１を介して矢示方向に押され、感光体ドラム１０への駆動伝達がなされる。
【００４４】
本実施形態の駆動連結部材では、両端支持梁部３５１の連結用突起部材３６の当接点とは反対側に一定の圧縮率で変形しながら面接触する流体封入型防振手段３７が設けられている。本発明は弾性的な変形挙動によって回転体と駆動源から成る駆動系の固有振動数を決定する両端支持梁部（第１の弾性部材）３５１と、両端支持梁部３５１の弾性的な挙動に作用し、その減衰特性を増加させる流体封入型防振手段（第２の弾性部材）３７とを駆動伝達部に有するもので、以下これに関して詳しく説明する。
【００４５】
本実施形態の連結用弾性体３５はポリアセタール（ＰＯＭ）を材料とする樹脂成型部材であって、例えば３本のネジによって駆動歯車３４に強固に固定されている。両端支持梁部３５１は、厚さ１．８ｍｍ、長さ３５ｍｍの両端固定の両持梁であって、これにより固有振動数が決定する。連結用弾性体３５の材料としては、上記以外にＡＢＳ樹脂、ＳＵＳ合金、亜鉛メッキ綱板（ＳＥＣＣ−Ｃ−２０／２０）、アルミニウム合金等弾性特性を有した工業用樹脂材や金属材を選択的に用いることができる。また実施形態においては、両端支持梁部３５１の形態をなしているが、図３（ｃ）に示すような片持ち支持梁部３５２の形態をなしていても差し支えない。
【００４６】
なお、図３中の一点鎖線の矢印は、連結用突起部材３６の連結用弾性体３５への挿入方向、及び駆動歯車３４と連結用弾性体３５の回転方向を示す。
図４に連結手段の他の実施の形態を示す。なお、図中で図３と同じ機能を有する部分には同符号を付している。
【００４７】
図４（ａ）の斜視図で示すように、両端支持梁部３５１を有した連結用弾性体３５は、フランジ１０１の端面に設けられ、両端支持梁部３５１がフランジ１０１のほぼ半径方向となる位置関係に固設されている。そして両端支持梁部３５１には、流体封入型防振手段３７が当接した形で圧入されている。また、駆動歯車３４の端面には棒状で剛体の連結用突起部材３６が固設されていて、組立られた状態では図４（ｂ）に示すように連結用突起部材３６は両端支持梁部３５１のほぼ中央位置に当接し、駆動歯車３４の回転に伴って連結用突起部材３６は両端支持梁部３５１を矢示方向に押して、感光体ドラム１０への駆動伝達が行われる。
【００４８】
図５（ａ）は流体封入型防振手段３７の断面図、図５（ｂ）は流体封入型防振手段３７のＡ−Ａ断面図である。
【００４９】
流体封入型防振手段３７は、連結用弾性体３５の可撓性梁状部（両端支持梁部３５１又は片持ち支持梁部３５２）に当接する側に粘弾性部材３７１と、粘弾性部材３７１に閉蓋された箱体３７０とから成る。箱体３７０内のほぼ中央には、流体流通用のオリフィス３７２Ａを有する仕切り板３７２が固定されている。箱体３７０の内部は、仕切り板３７２により仕切られた上方の第１の流体室３７３と、下方の第２の流体室３７４と、第２の流体室３７４と最下方の空気室３７５とを移動可能に仕切る防振ゴム膜部材３７６とを備えている。第１の流体室３７３と第２の流体室３７４には、粘性流体が密封収容され、空気室３７５には空気又は気体が封入されている。
【００５０】
連結用弾性体３５としては、ポリアセタール（ＰＯＭ）、ＡＢＳ等の樹脂、又はステンレス鋼（ＳＵＳ）、ＳＥＣＣ、アルミニウム合金等が用いられる。流体封入型防振手段３７の防振ゴム部材３７６としては、エチレンプロピレンゴム（ＥＰＤＭ）、シリコンゲル、オイル含浸多孔質ゴム、ブチルゴム、クロロプレンゴム、熱可塑性エラストマー、熱可塑性樹脂に高い振動吸収性能を付加した高機能材料が用いられる。粘性流体としては、シリコンオイル、電気粘性流体（ＥＲ流体）、電気磁気粘性流体（ＥＭＲ流体）等が用いられる。
【００５１】
本実施形態の粘弾性部材３７１には、クロロプレンゴム（ＣＲ）、エチレンプロピレンゴム（ＥＰＤＭ）、シリコンゲル、オイル含浸多孔質ゴム、ブチルゴム、熱可塑性エラストマー、熱可塑性樹脂に高い振動吸収性能を付加した高機能材料が用いられる。
【００５２】
流体封入型防振手段３７は、ＪＩＳゴム硬度が２０度ないし１００度、好ましくは４０度ないし８０度の間にある弾性体で、流体封入型防振手段３７内での内部摩擦の大きさを表す力学的損失係数ｔａｎδが０．３以上、好ましくは０．５以上の粘弾性体に構成し、前記回転体１０又は該回転体１０と一体回転するフライホイールと、連結用弾性体３５と、流体封入型防振手段３７から成る駆動伝達系のバネ定数や減衰係数で成り立つねじりの固有振動数が５〜６０Ｈｚにコントロールすることができる。
【００５３】
このような特性を有した流体封入型防振手段３７は、図３（ｂ）に示すように圧縮率１％から１５％の予め圧縮された状態で、可撓性梁状部３５１の連結用突起部材３６の当接点とは反対側に一定面積で面接触している。
【００５４】
本発明者は、慣性モーメント２７０００ｇｃｍ２の感光体ドラム１０について、ＪＩＳゴム硬度が６１度の流体封入型防振手段３７を用い、圧縮率１０％をもって可撓性梁状部３５１の裏面側に当接するよう構成し、損失係数ｔａｎδが１．９、ねじりの固有振動数が１５Ｈｚの可撓性梁状部３５１に対して流体封入型防振手段３７を当接することにより、回転体１０の慣性モーメントは１００００ｇ・ｃｍ²〜３００００ｇ・ｃｍ²で伝達係数のゲインの低減を可能とし、最適な防振特性が得られた。
【００５５】
図６は本発明の回転体の駆動装置を、ベルト感光体駆動に適用した実施の形態を示す構成図である。なお、図中で図２と同じ機能を有する部分には同符号を付している。また、前記実施の形態と異なる点を説明する。
【００５６】
駆動用モータ（駆動源）Ｍ１による駆動力が歯車３１から駆動歯車３４に伝達され、駆動歯車３４内に設けられた連結用弾性体３５と、フライホイール１０４と一体をなす連結用突起部材３６とから成る連結手段を介してフライホイール１０４に伝達される。フライホイール１０４の駆動軸１０５はフライホイール１０４と連結されているが、駆動歯車３４とは連結していない。そのため、駆動軸１０５と駆動歯車３４とは別体として回転し、駆動歯車３４の駆動は、駆動軸を通して伝達せず、連結用弾性体３５と連結用突起部材３６とから成る連結手段を介して伝達される。
【００５７】
フライホイール１０４に伝達された速度ムラは、連結手段とフライホイール１０４の慣性により速度ムラが低減しており、この駆動回転は、ベルトカートリッジ１０６を着脱可能とする連結部材（カップリング）１０７を介して駆動ローラ１０８に伝達され、駆動ローラ１０８と従動ローラ１０９間に巻回されたベルト感光体１１０を防振して高精度に駆動することが出来る。
【００５８】
図７（ａ）は連結部材（カップリング）１０７の側面図、図７（ｂ），（ｂ）は連結部材１０７の断面図を示す。
【００５９】
連結部材１０７は、感光体側の連結継ぎ手１０７Ａと、フライホイール１０４側の連結継ぎ手１０７Ｂとから成る。連結継ぎ手１０７Ａは複数の凸部を有する雄型であり、連結継ぎ手１０７Ｂは複数の凹部を有する雌型である。連結継ぎ手１０７Ａを連結継ぎ手１０７Ｂとを軸方向を一致させて嵌合させることにより、感光体側の駆動軸とフライホイール１０４側の駆動軸とが連結される。
【００６０】
図８は加振周波数と伝達関数のゲイン（入力周波数に対する出力周波数に比を示す振動伝達率）との関係を示す特性図である。
【００６１】
従来のソリッド型の防振ゴムは、損失係数を大きくすると、共振は抑えられるが、防振域は悪化の方向にゆくという特性をもつのに対して、粘性流体とオリフィスと防振ゴム部材との組み合わせにより、共振領域では損失係数を大きく、防振領域では損失係数を小さくできることから、図６に示すような理想的な振動特性を示す。
【００６２】
上記の構成により、慣性体（駆動歯車、フライホイール、感光体ドラム、ベルト感光体の駆動ローラ等）の慣性モーメントと弾性部材でねじりの固有振動数を支配的に、流体封入型防振手段３７で減衰係数を支配的に自在にコントロールすることができ、設計の自由度が格段に向上する。感光体駆動系の固有振動数と減衰係数を自由に設定出来るということは、具体的な効果として、固有振動数よりも高周波の領域においては、伝達関数のゲインが本来低下する領域にあることにより、速度ムラが低減し、また、減衰部材の効果で、伝達関数のゲインそのものが低減するという効果により、固有振動数近傍の共振レベルが低くなるという効果として現れ、全体として、感光体駆動に関わる速度ムラが効率よく低減し、その結果、感光体駆動精度が著しく向上するという効果を得ることが出来る。
【００６３】
また、流体封入型防振手段３７の粘弾性部材３７１を採用することにより、従来のソリッド型の粘弾性部材に比較して、共振ゲインが同程度であれば、流体封入型防振手段３７の方が振動減衰領域のゲインが下げられるので、より速度ムラが低減する（図８参照）。
【００６４】
最近では、外力の変化に対応して、理想的な振動絶縁特性が得られるように、アクティブに動特性を制御できる制御型防振装置が開発されている。これは、メカニカルな制御方式のものと、電気粘性流体（ＥＲ流体）を利用した制御方式のものとがある。ＥＲ流体は、電場内に置くと電界の強さに応じて粘性が変化する性質を有する流体で、その反応も可逆的で反応時間も短いという特徴を有する。また、電気磁気粘性流体（ＥＭＲ流体）は、電界及び磁界に感応する複合粒子を電気絶縁性溶媒に分散させた流体であり、電界と磁界の同時印加による相乗効果によって、ＥＭＲ流体の剪断応力を可変制御する。
【００６５】
図９は回転体の駆動装置の他の実施の形態を示すブロック図である。
【００６６】
前記流体封入型防振手段３７は、電界発生手段及び／又は磁界発生手段１１１に接続され、流体制御部１１２により可変制御される。また、駆動用モータＭ１は、モータ制御部１１３により制御される。
【００６７】
感光体ドラム１０の回転体負荷条件や、ラインスピードが変化したことが検知されると、プロセス制御部１１４は流体制御部１１２及びモータ制御部１１３を制御して、ＥＲ流体やＥＭＲ流体の粘度を可変する制御を行い、加振周波数や固有振動数の変化に対して最適な防振特性を得ることができる。
【００６８】
図１０は、ＥＲ流体やＥＭＲ流体を用いて制御を行った場合の伝達関数の変化を示す特性図である。
【００６９】
ラインスピードが２通りある場合の機械において、モータ制御部１１３からラインスピードが変化した場合のモータ回転数情報をもとに流体の粘度を制御することにより伝達関数の固有振動数と減衰係数を変化させ速度ムラが低減するように制御する。即ち、ラインスピード１の時には、流体粘度小に制御し、ラインスピード２の時には、流体粘度大に制御する。
【００７０】
この結果、共振領域近傍の速度ムラや、更に高周波の速度ムラも効率よく低減出来、更に現像駆動部からの振動、或いはクリーニングブレード、転写ローラ等の負荷変動等の外乱に対して強い、安定した駆動系が得られる。また、負荷条件や、ラインスピードが変化した場合においても最適な防振特性が得られ、安定した駆動系が得られる。
【００７１】
図１０は粘性流体を制御した場合の伝達関数の変化とラインスピードの変化に伴う速度ムラ成分の位置を表しており、これらの関係が共振しなように伝達関数を制御している。
【００７２】
図１１（ａ）は回転体の駆動装置の更に他の実施の形態を示すブロック図、図１１（ｂ）は流体封入型防振手段３８の断面図である。なお、図中で図５、図９と同じ機能を有する部分には同符号を付している。また、前記実施の形態と異なる点を説明する。これは複数のオリフィス３８２Ａ，３８２Ｂを持つ流体封入型防振手段を適用して、制御を行った実施の形態である。
【００７３】
前記箱体３７０内に固定された仕切り板３８２には、第１のオリフィス３８２Ａと第２のオリフィス３８２Ｂとが穿設されている。仕切り板３８２の下面側には、可動板３８１が摺動可能に設けられている。可動板３８１には開口３８１Ａが穿設されている。可動板３８１は駆動モータＭ２により移動される。仕切り板３８２の第２のオリフィス３８２Ｂと、可動板３８１の開口３８１Ａとが一致したとき、この開口位置において第１の流体室３７３内の流体と、第２の流体室３７４とが連通する。なお、可動板３８１の代わりに開口３８１Ａに電磁開閉弁を設けてもよい。また、オリフィスの数は２個に限定されるものではなく、３個以上設けることも可能である
図１２は、メカニカル制御を行った場合の伝達関数の変化を示す特性図である。
【００７４】
ラインスピードが２通りある場合の機械において、モータ制御部１１３からラインスピードが変化した場合のモータ回転数情報をもとに流体の粘度を制御することにより伝達関数の固有振動数と減衰係数を変化させ速度ムラが低減するように制御する。即ち、ラインスピード１の時には、流体粘度小に制御し、ラインスピード２の時には、流体粘度大に制御する。
【００７５】
主な構成は図１１に示す通りである。ラインスピードが２通りある場合の機械において、モータ制御部１１３からラインスピードが変化した場合のモータ回転数情報をもとに、オリフィスの数を制御することにより伝達関数の固有振動数と減衰係数を変化させ速度ムラが低減するように制御する。
【００７６】
図１２は制御した場合の伝達関数の変化とラインスピードの変化に伴う速度ムラ成分の位置を表しており、これらの関係が共振しなように伝達関数を制御している。即ち、ラインスピード１の時には、オリフィス数を２個（３８２Ａ，３８２Ｂ）に制御し、ラインスピード２の時には、オリフィス数を１個（３８２Ａ）に制御する。
【００７７】
図１３は、本発明の回転体の駆動装置を適用したカラー画像形成装置の他の実施の形態を示す断面構成図である。
【００７８】
なお、図面に使用されている符号について、図１と同じ機能を有する部分には、同符号を付している。また、前記の実施の形態と異なる点を説明する。
【００７９】
ドラム状の像担持体である感光体ドラム１０は、例えば、透明アクリル樹脂の透明部材によって形成される円筒状の透明樹脂基体を内側に設け、透明の導電層及び有機感光体層（ＯＰＣ）を該基体の外周に形成したものであり、接地された状態で図１３の矢印で示す方向に回転される。感光体ドラム１０に駆動源からの駆動力を伝達する駆動連結手段に、前記可撓性梁状部３５１を有する連結用弾性体３５と流体封入型防振手段とを設けることにより、感光体ドラム１０は高精度に駆動される。
【００８０】
本発明に係わるカラー画像形成装置は、像担持体１０の周囲に、帯電手段、像露光手段、現像手段とから成る画像形成ユニットを複数組（図示４組）配設したものである。
【００８１】
１１Ｙ，１１Ｍ，１１Ｃ，１１Ｋはスコロトロン帯電器（以下、帯電器１１（Ｙ，Ｍ，Ｃ，Ｋ）という）で、感光体ドラム１０の前述した有機感光体層に対し所定の電位に保持されたグリッドと放電ワイヤによるコロナ放電とによって帯電作用を行い、感光体ドラム１０に対し一様な電位を与える。
【００８２】
１３Ｙ，１３Ｍ，１３Ｃ，１３Ｋは、画像信号に基づいた像露光を行う像露光手段（以下、露光光学系１３（Ｙ，Ｍ，Ｃ，Ｋ）と称す）で、感光体ドラム１０の軸方向に配列したＬＥＤと等倍結像系であるセルフォックレンズとから構成される露光光学系で、別体の画像読み取り装置によって読み取られた各色の画像信号がメモリより順次取り出されて前記の各露光光学系１３（Ｙ，Ｍ，Ｃ，Ｋ）にそれぞれ電気信号として入力され、感光体ドラム１０の回転（副走査）によって潜像を形成する。各露光光学系１３（Ｙ，Ｍ，Ｃ，Ｋ）は何れも光学系支持手段として設けた支持部材１３０に取り付けられて前記感光体ドラム１０の基体内部に収容される。
【００８３】
１４Ｙ，１４Ｍ，１４Ｃ，１４Ｋは、イエロー（Ｙ），マゼンタ（Ｍ），シアン（Ｃ）及び黒色（Ｋ）の各現像剤を収容する現像器で、それぞれ感光体ドラム１０の周面に対し所定の間隙を保って回転する現像スリーブ１４０と、剥ぎ取り磁極を有するマグネットローラ１４２を備えている。
【００８４】
前記の各現像器１４（Ｙ，Ｍ，Ｃ，Ｋ）は、前述した帯電器１１（Ｙ，Ｍ，Ｃ，Ｋ）による帯電，露光光学系１３（Ｙ，Ｍ，Ｃ，Ｋ）による像露光によって形成される感光体ドラム１０上の静電潜像を現像バイアス電圧の印加により非接触の状態で反転現像する。
【００８５】
原稿画像は本装置とは別体の画像読み取り装置において、撮像素子により読み取られた画像或いはコンピュータで編集された画像を、Ｙ，Ｍ，Ｃ及びＫの各色別の画像信号として一旦メモリに記憶し格納される。
【００８６】
画像記録のスタートにより感光体駆動モータの始動により感光体ドラム１０を反時計方向（図示矢方向）へと回転し、同時に帯電器１１Ｙの帯電作用により感光体ドラム１０に電位の付与が開始される。
【００８７】
感光体ドラム１０は電位を付与されたあと、前記の露光光学系１３Ｙにおいて第１の色信号即ちイエローＹの画像信号に対応する電気信号による露光が開始されドラムの回転走査によってその表面の感光層に原稿画像のイエロー（Ｙ）の画像に対応する静電潜像を形成する。
【００８８】
前記の潜像は現像器１４Ｙにより現像スリーブ１４０上の現像剤が非接触の状態で反転現像され感光体ドラム１０の回転に応じイエロー（Ｙ）のトナー像が形成される。
【００８９】
次いで感光体ドラム１０は前記イエロー（Ｙ）のトナー像の上に更に帯電器１１Ｍの帯電作用により電位を付与され、露光光学系１３Ｍの第２の色信号即ちマゼンタ（Ｍ）の画像信号に対応する電気信号による露光が行われ、現像器１４Ｍによる非接触の反転現像によって前記のイエロー（Ｙ）のトナー像の上にマゼンタ（Ｍ）のトナー像が順次重ね合わせて形成していく。
【００９０】
同様のプロセスにより帯電器１１Ｃ、露光光学系１３Ｃ及び現像器１４Ｃによって更に第３の色信号に対応するシアン（Ｃ）のトナー像が、また帯電器１１（Ｋ）、露光光学系１３Ｋ及び現像器１４Ｋによって第４の色信号に対応する黒色（Ｋ）のトナー像が順次重ね合わせて形成され、感光体ドラム１０の一回転以内にその周面上にカラーのトナー像が形成される。
【００９１】
これ等各露光光学系による感光体ドラム１０の有機感光層に対する露光はドラムの内部より前述した露光波長に対し透明の基体を通して行われる。従って第２、第３及び第４の色信号に対応する画像の露光は何れも先に形成されたトナー像の影響を全く受けることなく行われ、第１の色信号に対応する画像と同等の静電潜像を形成することが可能となる。なお、各現像器１４（Ｙ，Ｍ，Ｃ，Ｋ）による現像作用に際しては、それぞれ現像スリーブ１４１に対し直流或いは更に交流を加えた現像バイアスが印加され、現像器１４（Ｙ，Ｍ，Ｃ，Ｋ）に収容された一成分或いは二成分現像剤による非接触現像が行われて、透明電導層を接地する感光体ドラム１０に対して非接触の反転現像が行われるようになっている。
【００９２】
感光体ドラム１０の周面上に形成されたカラーのトナー像は、一旦中間転写手段として設けた中間転写ベルト４０の周面に転写される。中間転写ベルト４０はローラ４１，４２，４３及び駆動ローラ４４の間に張架され、駆動ローラ４４に伝達される動力により感光体ドラム１０の周速度に同期して時計方向に循環して搬送される。
【００９３】
中間転写ベルト４０には駆動ローラ４４とローラ４２の間のベルト面を感光体ドラム１０の周面に接し、駆動ローラ４４外周のベルト面を転写部材である転写ローラ４５に接していて、それぞれの接触位置においてトナー像の転写域を形成している。
【００９４】
駆動ローラ４４に駆動源からの駆動力を伝達する駆動連結手段に、前記可撓性梁状部３５１を有する連結用弾性体３５と流体封入型防振手段とを設けることにより、感光体ドラム１０は高精度に駆動される。
【００９５】
感光体ドラム１０周面に付着した状態にある複数色から成るカラートナー像は、先ず前記の中間転写ベルト４０との間の接触位置においてローラ４２へのトナーと反対極性のバイアス電圧の印加により順次中間転写ベルト４０の周面側に転写される。即ち、感光体ドラム１０上のカラートナー像は、接地したローラ４１の案内によりトナーを散らすことなく転写域へと搬送され、ローラ４２に対する１〜２ｋＶのバイアス電圧の印加によって中間転写ベルト４０側に効率良く転写される。
【００９６】
感光体ドラム１０にはクリーニング装置５０が、中間転写ベルト４０にはクリーニング装置４６が圧接し、それぞれの備えるブレードが常時圧接されていて、残留した付着トナーの除去がなされて周面は常に清浄な状態に保たれている。
【００９７】
一方、給紙カセット（図示せず）の給紙ローラ２２Ｂの作動により転写材Ｐが搬出されてタイミングローラ２３に給送され、中間転写ベルト４０上のカラートナー像の搬送に同期して転写ローラ４５の転写域へと給紙される。
【００９８】
転写ローラ４５は中間転写ベルト４０の周速度に同期して反時計方向に回動されていて、給紙された転写材Ｐは転写ローラ４５と接地状態にあるローラ３３の間のニップ部の形成する転写域において中間転写ベルト４０上のカラートナー像に密着され転写ローラ４５への１〜２ｋＶのトナーと反対極性のバイアス電圧の印加により順次カラートナー像は転写材Ｐ上に転写される。
【００９９】
カラートナー像の転写を受けた転写材Ｐは除電され、搬送板２７を介して定着装置２４に搬送され、熱ローラ２４１と圧着ローラ２４２との間に挟着搬送して加熱され、トナーを溶着して定着がなされたのち排紙ローラ２５Ａを介して装置外部に排出される。
【０１００】
感光体ドラム１０及び駆動ローラ４４に、可撓性梁状部３５１を有する連結用弾性体３５と流体封入型防振手段とを設けることにより、感光体ドラム１０及び中間転写ベルト４０は高精度に駆動され、高画質のカラー画像を安定して出力することができる。
【０１０１】
図１４は像担持体として、中間転写ドラム６０を使用したカラー画像形成装置の断面構成図である。この中間転写ドラム６０を使用した場合には、回動する感光体ドラム１０上に形成された静電潜像を現像スリーブ１４０とマグネットローラ１４２とを備えた現像器１４Ｙにより現像してＹ色トナー像を形成し、このＹ色トナー像を感光体ドラム１０から中間転写ドラム６０に転写し、同様にして、感光体ドラム１０上に形成された静電潜像を現像器１４Ｍにより現像してＭ色トナー像を形成し、このＭ色トナー像を感光体ドラム１０から中間転写ドラム６０に転写し、以下同様にして、Ｃ色トナー像及びＫ色トナー像を感光体ドラム１０から中間転写ドラム６０に順次転写する。更に、中間転写ドラム６０と転写ローラ１７とが接する転写部において、多色トナー像（Ｙ，Ｍ，Ｃ，Ｋ）を転写材Ｐに一括して静電転写したのち、分離手段１８により分離して、定着装置２４により画像を定着する。
【０１０２】
このカラー画像形成装置においても、感光体ドラム１０及び中間転写ドラム６０に、可撓性梁状部３５１を有する連結用弾性体３５と流体封入型防振手段とを設けることにより、感光体ドラム１０及び中間転写ドラム６０は高精度に駆動され、高画質のカラー画像を安定して出力することができる。
【０１０３】
図１５は、本発明の回転体の駆動装置を適用したカラー画像形成装置の更に他の実施の形態を示す断面構成図である。
【０１０４】
このカラー画像形成装置は、図１３と同様に、像担持体１０の周囲に、帯電手段１１（Ｙ，Ｍ，Ｃ，Ｋ）、像露光手段１３（Ｙ，Ｍ，Ｃ，Ｋ）、現像手段１４（Ｙ，Ｍ，Ｃ，Ｋ）とから成る画像形成ユニットを複数組（図示４組）配設したものである。但し、像担持体として可撓性の無端ベルト状の感光体（以下、ベルト感光体とも称す）１１０を、像露光手段１４（Ｙ，Ｍ，Ｃ，Ｋ）としてレーザビーム走査光学装置を使用したものである。
【０１０５】
ベルト感光体１１０は、駆動ローラ１０８及び従動ローラ１０９Ａ，１０９Ｂに張架され、テンションローラ１１６の作用により緊張状態にされ、内周面に設けられたバックアップ部材１１７により局部的に当接しながら、図示の時計方向に回動する。バックアップ部材１１７は、現像スリーブ１４１（Ｙ，Ｍ，Ｃ，Ｋ）の現像領域及び像露光手段１３（Ｙ，Ｍ，Ｃ，Ｋ）の結像位置を位置決めしている。
【０１０６】
張架された無端ベルト状の感光体１１０の外周側面には、４組の帯電手段１１（Ｙ，Ｍ，Ｃ，Ｋ）、像露光手段１３（Ｙ，Ｍ，Ｃ，Ｋ）、現像手段１４（Ｙ，Ｍ，Ｃ，Ｋ）から成る像形成手段が設けられている。
【０１０７】
画像記録のスタートにより、駆動モータが回動して駆動ローラ１０８を介してベルト感光体１１０は図示の時計方向へと回転し、スコロトロン帯電器１１（Ｙ）の帯電作用によりベルト感光体１１０への電位の付与が開始される。ベルト感光体１１０は電位を付与されたあと、像露光手段１３（Ｙ）において第１の色信号即ちイエロー（Ｙ）の画像信号に対応する電気信号による露光が開始され、ベルトの回転（副走査）によってその表面の感光層に現像画像のイエロー（Ｙ）の画像に対応する静電潜像を形成する。この潜像は現像器１４（Ｙ）により現像スリーブ１４１（Ｙ）上に付着搬送された現像剤が非接触の状態で反転現像され、ベルト感光体１１０の回転に応じてイエロー（Ｙ）のトナー像が形成される。
【０１０８】
次いでベルト感光体１１０はイエロー（Ｙ）のトナー像の上に更にスコロトロン帯電器１１（Ｍ）の帯電作用により電位が付与され、像露光手段１３（Ｍ）の第２の色信号即ちマゼンタ（Ｍ）の画像信号に対応する電気信号による露光が行われ、現像器１４（Ｍ）による非接触の反転現像によって前記のイエロー（Ｙ）のトナー像の上にマゼンタ（Ｍ）のトナー像が重ね合わせて形成される。
【０１０９】
同様のプロセスによりスコロトロン帯電器１１（Ｃ）、像露光手段１３（Ｃ）及び現像器１４（Ｃ）によって更に第３の色信号に対応するシアン（Ｃ）のトナー像が、またスコロトロン帯電器１１（Ｋ）、像露光手段１３（Ｋ）及び現像器１４（Ｋ）によって第４の色信号に対応する黒色（Ｋ）のトナー像が順次重ね合わせて形成され、ベルト感光体１１０の一回転以内にその周面上にカラーのトナー像が形成される。
【０１１０】
現像器１４（Ｙ），１４（Ｍ），１４（Ｃ）及び１４（Ｋ）による現像作用に際しては、それぞれ現像スリーブ１４１（Ｙ），１４１（Ｍ），１４１（Ｃ）及び１４１（Ｋ）に対し直流或いは更に交流を加えた現像バイアスが印加され、現像スリーブ１４１上に付着した一成分或いは二成分現像剤による非接触現像が行われて、導電層を接地したベルト感光体１１０に対してベルト感光体１１０の帯電と同極性の直流バイアスが印加された現像スリーブ１４１から感光体上の露光部にトナーを付着させる非接触の反転現像が行われる。
【０１１１】
かくして、ベルト感光体１１０の周面上に形成されたカラーのトナー像はスコロトロン帯電器１１（Ｆ）によって付着トナーの電位が揃えられたのち転写前露光器１２によって除電が行われ、転写部において、給紙装置である給紙カセット２０（Ａ），２０（Ｂ）或いは手差し部から送り出され、レジストローラ対２３へと搬送され、レジストローラ対２３の駆動によってベルト感光体１１０上のトナー像領域と同期して給紙される転写紙上に、ベルト感光体１１０の駆動用の駆動ローラ１０８の下部に対向して配置された転写ローラ１７により転写される。
【０１１２】
トナー像の転写を受けた転写紙は、駆動ローラ１０８の曲率に沿ったベルト感光体１１０周面より分離されたのち、定着装置２４へ搬送され、定着装置２４において加熱・圧着されてトナーが転写紙上に溶着・定着されて定着装置２４より排出され、排紙ローラ対２５Ａ，２５Ｂ，２５Ｃにより搬送されて、上部に設けられた排紙トレイ２６に転写紙上のトナー像面を下面にして排出される。
【０１１３】
一方、転写紙を分離したベルト感光体１１０はクリーニング装置１９においてクリーニングブレード１９１によってベルト感光体１１０面の摺擦がなされ、残留トナーの除去・清掃がなされて、次の原稿画像のトナー像の形成を続行するか、もしくは一旦停止して待機する。なお次の原稿画像のトナー像の形成が続いて行われるときは、帯電前除電器１２によるベルト感光体１１０の感光体面への露光が行われて前歴の除去がなされる。
【０１１４】
この実施の形態においても、駆動ローラ１０８に、図示しない可撓性梁状部３５１を有する連結用弾性体３５と流体封入型防振手段とを設けることにより、駆動ローラ１０８を速度変動なく、一定の速度で移送できる。従ってベルト感光体１１０は高精度に駆動され、高画質のカラー画像を安定して出力することができ、画像品質を著しく向上させることができる。
【０１１５】
また、本発明の回転体の駆動装置は、例えばドラム状の回転体に感光フィルムを巻き付け、回転体を一様速度で回転させながら、ポリゴンミラー等によって走査を行うレーザ光で感光フィルム上に画像記録を行う記録装置に適用しても優れた効果を得ることができる。
【０１１６】
本発明によるときは、第１の弾性部材（梁部）によって回転体のねじりの固有振動数を支配的に、第２の弾性部材（粘弾性体）によって減衰係数を支配的に自在にコントロールすることが出来、設計の自由度が格段に向上する。回転体駆動系の固有振動数と減衰係数を自由に設定できるということは、具体的な効果として、固有振動数よりも高周波の領域においては、伝達関数のゲインが本来低下する領域にあることにより、速度ムラが低減し、また、減衰部材の効果で、伝達関数のゲインそのものが低減するという効果により、固有振動数近傍の共振レベルが低くなるという効果として現れ、全体として回転体駆動に関わる速度ムラが効率よく低減し、回転体駆動精度が著しく向上するという効果を得ることができる。
【０１１７】
この結果、共振領域近傍の速度ムラ、画像形成装置にあっては現像駆動部からの振動、或いはブレード、転写ローラ等の負荷変動等の外乱に対して強い、安定した駆動系が得られる。
【０１１８】
【発明の効果】
本発明による回転体の駆動装置により、負荷変動や、駆動系の速度ムラによる影響を極めて小さく出来るため、回転体や画像を形成する感光体ドラムは、常に高精度かつ安定した回転が得られる。また、負荷条件や、ラインスピードが変化した場合においても最適な防振特性が得られるため従来のソリッド型に比較して、より高精度な駆動が可能である（請求項１、２）。
【０１１９】
本発明による回転体の駆動装置を備えた画像形成装置は、感光体の速度ムラに起因する主要な画像トラブルであるスモールピッチ・バンディングを著しく低減させ、これを人間に認識出来ないレベルとし、高画質の画像を安定して提供することが出来る（請求項７、８）。
【図面の簡単な説明】
【図１】本発明の回転体駆動装置を装着した画像形成装置の一例であるカラープリンタの断面構成図。
【図２】感光体ドラムと駆動機構を示す斜視図及び部分断面図。
【図３】感光体ドラムと連結手段を示す斜視図及び連結用弾性体の構造を示す正面図。
【図４】感光体ドラムと連結手段の他の実施の形態を示す斜視図及び連結用弾性体の構造を示す正面図。
【図５】流体封入型防振手段の断面図及び流体封入型防振手段のＡ−Ａ断面図。
【図６】本発明の回転体駆動装置を、ベルト感光体駆動に適用した実施の形態を示す構成図。
【図７】連結部材の側面図及び断面図。
【図８】加振周波数と伝達関数のゲインとの関係を示す特性図。
【図９】回転体の駆動装置の他の実施の形態を示すブロック図。
【図１０】ＥＲ流体やＥＭＲ流体を用いて制御を行った場合の伝達関数の変化を示す特性図。
【図１１】回転体の駆動装置の更に他の実施の形態を示すブロック図及び流体封入型防振手段の断面図。
【図１２】メカニカル制御を行った場合の伝達関数の変化を示す特性図。
【図１３】本発明の回転体駆動装置を適用したカラー画像形成装置の他の実施の形態を示す断面構成図。
【図１４】本発明の回転体駆動装置を適用した中間転写ドラムを備えたカラー画像形成装置の実施の形態を示す断面構成図。
【図１５】本発明の回転体駆動装置を適用したベルト感光体を備えたカラー画像形成装置の実施の形態を示す断面構成図。
【符号の説明】
１０ 回転体（感光体ドラム、像担持体）
１０１ フランジ
１０４ フライホイール
１０８，４４ 駆動ローラ
１１０ ベルト感光体
１１１ 電界磁界発生手段
１１２ 流体制御部
１１３ モータ制御部
１１４ プロセス制御部
１１５ オリフィス制御部
３０ 駆動機構
３４ 駆動歯車（駆動伝達部材）
３５ 連結用弾性体（弾性体部材、駆動連結部材）
３５１ 両端支持梁部（可撓性梁状部）
３５２ 片持ち支持梁部（可撓性梁状部）
３６ 連結用突起部材（従動連結部材）
３７，３８ 流体封入型防振手段
３７１ 粘弾性部材
３７２ 仕切り板
３７２Ａ，３８２Ａ，３８２Ｂ オリフィス
３７３ 第１の流体室
３７４ 第２の流体室
３７５ 空気室
３７６ 防振ゴム部材
３８１ 可動板
３８１Ａ 開口
Ｍ１，Ｍ２ 駆動モータ（駆動源）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a driving device for a rotating body that drives and rotates a rotating body such as a photoconductor, and an image forming apparatus that forms an image on a photoconductor that rotates by a digital method.
[0002]
[Prior art]
In an electrophotographic copying machine or printer, an electrostatic latent image is formed on the surface of a rotating cylindrical photosensitive member or a belt-shaped photosensitive member, and toner is applied to the formed electrostatic latent image. The toner image is adhered and developed, and the toner image is transferred and fixed on a recording sheet to obtain an image.
[0003]
Here, a cylindrical photosensitive member of the image forming apparatus, that is, a photosensitive drum or a driving roller for running the belt-like photosensitive member is referred to as a rotating member.
[0004]
When a speed fluctuation (rotational unevenness) occurs in the photosensitive member that should rotate at a uniform speed, a phenomenon of small pitch banding occurs, and jitter and image unevenness occur in the output image. This is particularly noticeable in the digital electrophotographic technique in which writing on the photoconductor is performed by scanning with a semiconductor laser. The fluctuation in the rotation speed of the photoconductor becomes the speed fluctuation in the sub-scanning direction of the writing system. This causes a slight shift in the interval of the image and causes a significant decrease in image quality.
[0005]
There have been many proposals regarding techniques for improving the accuracy of driving a rotating body that should rotate at a uniform rotational speed, but the following two flows can be seen.
[0006]
One flow is to incorporate a flywheel in the drive system, and conventional ones that facilitate the attachment and detachment of the flywheel are disclosed in Japanese Patent Laid-Open Nos. 7-281500 and 8-202205. JP-A Nos. 6-130872, 6-130874, 7-302025, and 8-202206 disclose a flywheel in a rotating body. Further, those which detect the frequency characteristics of the rotating body and optimize the inertial moment of the flywheel in relation to the excitation frequency are disclosed in JP-A-8-63041, 8-1-15411, and 8-220966. It is disclosed in the gazette.
[0007]
Another major flow is to absorb the vibration in the rotational direction of the drive transmission system by using a gear or a timing belt / pulley incorporating an elastic member in the middle of the rotating body drive system. Specifically, these are disclosed in JP-A-6-249321, JP-A-6-294453, JP-A-7-325445, JP-A-7-325446, and JP-A-8-54047.
[0008]
As described above, the use of a flywheel is the most effective technical means for improving the driving accuracy of a rotating body in the prior art. However, the device becomes larger and requires a large torque at the start of rotation. This is a fundamental problem. In addition, since the flywheel itself reduces rotational vibration by the kinetic energy of rotation, when the rotating body is rotated at a low speed, the flywheel having a larger diameter than that of the rotating body is required to be effective. It is necessary to adopt a wheel. Therefore, in order to avoid an increase in size of the apparatus, a functional limit has to be recognized even when a flywheel is provided in the rotating body.
[0009]
In recent years, the natural frequency of the drive system of a rotating body is obtained, and the drive system is designed taking into consideration the relationship with the excitation frequency, and the frequency response of the rotary system centered on the natural frequency is obtained and inertia The idea of changing the shape of the frequency characteristic, that is, the shape of the transfer function by designing the quantity, changing the peak position, and optimizing the drive system has been generalized. The biggest problem in this case is that, in consideration of moving the natural frequency to a low frequency region in one rotating body drive system, the diameter of the flywheel is necessarily increased or the weight thereof is increased. This means that the natural frequency f of the fundamental frequency is
[0010]
[Expression 1]

[0011]
This is equivalent to reducing the value of the natural frequency f by increasing the moment of inertia I.
[0012]
On the other hand, improving the driving accuracy by providing an elastic member in the middle of the drive system converts the vibration component in the rotational direction generated in the drive system into heat in the elastic member and dissipates it. Since the concept of the frequency characteristics and transfer function of the drive system is not included here, the effect cannot be predicted depending on the excitation frequency of the generated vibration and the configuration of the drive system, and the level of the effect varies.
[0013]
In Japanese Patent Application No. 9-74849, it is possible to easily control the natural frequency and the transfer gain. However, if the loss coefficient of the viscoelastic member is increased and the resonance gain is lowered, the gain of the vibration damping region is increased. As a result, there is a problem that the vibration proof property is lowered. Furthermore, when the load condition or line speed changes, the vibration frequency or natural frequency may change, and optimal vibration isolation characteristics may not be obtained.
[0014]
[Problems to be solved by the invention]
In the development of digital image forming apparatuses, as the performance has improved, the reproducibility of one dot line by laser writing has been strictly demanded, and the accuracy required for the drive system has also become severe. The accuracy required here is a level at which the uniformity in the sub-scanning direction of writing by the laser is guaranteed in relation to the visual sensitivity of the visual system, and the recording density is increased from 600 dpi to 2400 dpi, There is a need to drive a rotating body with high accuracy and no rotational unevenness that satisfies the high level that small pitch banding cannot be recognized by humans.
[0015]
For this reason, in the range of the prior art, high precision gears, dedicated drive, and large flywheels are generally used to increase the precision of driving the rotating body. However, the adoption of a flywheel inevitably increases the weight and equipment as described above. Furthermore, in order to provide an electrophotographic printer, the gear driving force is applied to a rotating body such as a photosensitive drum via an elastic member in order to provide a lightweight, compact, low-cost and highly accurate drive. A transmission structure has been proposed. However, in this technology, the elastic member alone has a great effect of reducing the speed unevenness above the natural frequency, but the gain in the resonance region increases, and the effect of speed unevenness in the vicinity of the resonance region and load fluctuations greatly affects the banding. There was a problem getting worse.
[0016]
The present invention has a new structure that solves these problems, and is lightweight, compact, low-cost, hardly affected by disturbances, etc., and achieves high-accuracy driving to achieve high-quality image output. An object is to provide a body drive device and an image forming apparatus.
[0017]
In Japanese Patent Application No. 9-74849, proposals have been made to solve these problems. However, in order to lower the resonance gain, if the loss coefficient of the viscoelastic member is increased, the gain in the vibration damping region is increased, and the vibration is prevented. There was a problem that the characteristics deteriorated. Furthermore, when the load condition or line speed changes, the vibration frequency or natural frequency may change, and optimal vibration isolation characteristics may not be obtained. The present invention has a novel structure that solves these problems, and is lightweight, compact, low-cost, hardly affected by disturbances, and the like, by driving a photoconductor drum, a belt photoconductor drive roller, and the like with high accuracy. An object of the present invention is to provide an image forming apparatus that outputs a high-quality image.
[0018]
[Means for Solving the Problems]
The rotating body drive device of the present invention that achieves the above object transmits the rotating body that is rotatably supported, a driving source that drives the rotating body, and a rotational driving force of the driving source to the rotating body. In the driving device for a rotating body having a driving member for driving, a driven member, and a connecting means, the connecting means comprises a driving connecting member and a driven connecting member, and the driving connecting member includes a flexible elastically deformable member. An elastic member having a conductive beam-like portion and a fluid-filled vibration isolating means fixed in surface contact with one surface of the flexible beam-like portion, and the driven connecting member has a connecting projection member. The connecting projection member is brought into contact with and connected to the flexible beam-like portion, and the rotational driving force of the driving source is transmitted to the rotating body through the connecting means. (Claim 1).
[0019]
The rotating body drive device of the present invention that achieves the above object includes a rotating body that is rotatably supported, a driving source that drives the rotating body, and a rotational driving force of the driving source applied to the rotating body. In a drive device for a rotating body having a drive member for transmitting, a driven member, and a transmitting means comprising a connecting means, the connecting means comprises a drive connecting member and a driven connecting member, and the drive connecting member is connected An elastic body member having an elastically deformable flexible beam-like portion, and a fluid-filled type fixed in surface contact with one surface of the flexible beam-like portion. Anti-vibration means is provided, and the connecting projection member of the drive connecting member is brought into contact with and connected to the flexible beam-like portion of the driven connecting member, and the rotational driving force of the drive source is applied to the connecting means. Is transmitted to the rotating body via That (claim 2).
[0020]
An image forming apparatus of the present invention that achieves the above object holds at least an image carrier that carries an image, an image forming unit that forms an image on the image carrier, and the image carrier or the image carrier. In an image forming apparatus, comprising: a drive source for driving and rotating a rotating body; and a transmitting means including a driving member, a driven member, and a connecting means for transmitting a rotational driving force of the driving source to the image carrier or the rotating body. The connecting means includes a driving connecting member and a driven connecting member, and the driving connecting member or the driven connecting member includes an elastic body member having a flexible beam-like portion that can be elastically deformed, and the flexible beam-like member. A fluid-filled vibration isolating means fixed in surface contact with one surface of the part, wherein the fluid-filled vibration-proof means includes a viscoelastic member on the side contacting the flexible beam-like part, A box that is closed by an elastic member. A partition plate having an orifice for fluid distribution, a first fluid chamber and a second fluid chamber partitioned by the partition plate, and an anti-vibration rubber film for movably partitioning the second fluid chamber and the air chamber The fluid contained in the first fluid chamber and the second fluid chamber of the fluid-filled vibration isolating means is an electrorheological fluid whose viscosity reversibly changes depending on whether the electric field is on or off, or an electric field Electromagnetic viscous fluid in which the shear stress of the fluid changes due to simultaneous application of a magnetic field, and is controlled to obtain optimal vibration isolation characteristics in accordance with changes in drive system load conditions and line speed (Claim 7).
[0021]
In addition, the image forming apparatus of the present invention that achieves the above object transmits a rotating body that is rotatably supported, a driving source that drives the rotating body, and a rotational driving force of the driving source to the rotating body. In the driving device for a rotating body having a driving member, a driven member, and a transmitting means comprising a connecting means, the connecting means comprises a driving connecting member and a driven connecting member, and the driving connecting member or the driven connecting member includes An elastic body member having an elastically deformable flexible beam-like portion; and a fluid-filled vibration isolating means fixed in surface contact with one surface of the flexible beam-like portion; The vibration isolating means has a viscoelastic member on the side in contact with the flexible beam-shaped portion, and a box body closed by the viscoelastic member, and the box body includes a plurality of fluid circulation channels. A partition plate having an orifice, and a first fluid chamber partitioned by the partition plate Two fluid chambers, an anti-vibration rubber film member that divides the second fluid chamber and the air chamber movably, and a plurality of on-off valves that can open and close the plurality of orifices, and the drive connecting member The driven connecting member connected to the driven connecting member or the driving connecting member connected to the driven connecting member is provided with a protruding member, and the protruding member is brought into contact with and connected to the flexible beam-like portion to drive the driving member. A driving means for transmitting the rotational driving force of the source to the rotating body via a connecting means comprising the driving connecting member and a driven connecting member, and for operating the on-off valve to be opened and closed, and a control for controlling the driving means And opens and closes a predetermined on-off valve so that the amount of fluid flowing through the orifice can be variably controlled, and control is performed so as to obtain optimal vibration isolation characteristics in accordance with changes in drive system load conditions and line speed. It is characterized by Than it (claim 8).
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Prior to the description of the embodiment of the present invention, the configuration and operation of a color printer which is an example of an image forming apparatus equipped with the rotating body (photosensitive drum) of the present invention will be described with reference to the cross-sectional configuration diagram of FIG.
[0023]
In this color printer, each color toner image sequentially formed on a photosensitive drum is superimposed, and then transferred onto a recording sheet at a time by a transfer unit to form a color image, and then separated from the image carrier surface by a separating means. This is a color image forming apparatus of a peeling type.
[0024]
In FIG. 1, reference numeral 10 denotes a cylindrical photoconductor drum having a diameter of 120 mm, which is formed by coating an OPC photoconductor (organic photoconductor) on a drum base, and is grounded and linearly drawn at a speed of 100 mm / sec in the clockwise direction in the drawing. Is driven and rotated. A scorotron charger 11 has a high potential V with respect to the circumferential surface of the photosensitive drum 10. _H The uniform charging of the grid potential V _G Is applied by a corona discharge by a grid and a corona discharge wire held at a potential. Prior to charging by the scorotron charger 11, in order to eliminate the history of the photoconductor up to the previous printing, exposure by a pre-charge neutralizer (PCL) 12 using a light emitting diode or the like is performed to neutralize the peripheral surface of the photoconductor. deep. The history of the photoconductor means an image pattern remaining on the photoconductor formed by the charging and image exposure in the preceding image formation, and is also called a photoconductor memory.
[0025]
After the photosensitive drum 10 is uniformly charged, the image exposure unit 13 performs image exposure based on the image signal. The image exposure means 13 scans the optical path bent by a reflection mirror through a rotating polygon mirror, fθ lens, and cylindrical lens using a laser diode (not shown) as a light source. A latent image is formed by the rotation of the photosensitive drum 10. Is done. In this embodiment, the character portion is exposed and the exposed portion potential V is obtained. _L Is charged potential V _H A reversal latent image that has a lower potential than that is formed.
[0026]
At the periphery of the photosensitive drum 10, developing units 14Y, 14M, each incorporating therein a two-component developer composed of a toner such as yellow (Y), magenta (M), cyan (C), black (K) and a carrier, respectively. A developing device 14 consisting of 14C and 14K is provided.
[0027]
First, yellow of the first color is developed by a developer carrier (hereinafter referred to as a developing sleeve) 141 that contains a magnet and rotates while holding the developer. The developer consists of a carrier with a ferrite core and an insulating resin coating around it, and a toner containing polyester as a main material and a pigment according to the color and a charge control agent, silica, titanium oxide, etc. The developer is regulated to a developer layer thickness of 100 to 600 μm on the developing sleeve 141 by a developer layer forming means to be described later, and is conveyed to the developing region.
[0028]
The gap between the developing sleeve 141 and the photosensitive drum 10 in the developing region is set to 0.2 to 1.0 mm, which is larger than the developer layer thickness, and the AC bias V is set therebetween. _AC And DC bias V _DC Are superimposed and applied. DC bias V _DC And photoreceptor charging potential V _H Since the toner charge has the same polarity, the AC bias V _AC When the toner is given an opportunity to leave the carrier by the DC bias V _DC Higher potential photoconductor charging potential V _H DC bias V _DC Lower exposure area potential V _L It adheres to the part and is visualized (reversal development).
[0029]
After the first color visualization is completed, the second color magenta image forming process is started, and uniform charging is performed again by the scorotron charger 11, and a latent image is formed by the second color image data by the image exposure means 13. Is done. At this time, the charge removal by the PCL 12 performed in the first color image forming process is not performed because the toner adhering to the image portion of the first color is scattered due to a rapid decrease in the surrounding potential.
[0030]
The photosensitive member charging potential V is again applied over the entire surface of the photosensitive drum 10. _H A portion of the photosensitive member charged with no color image is subjected to development with a latent image similar to that of the first color, but developed again with respect to the portion with the first color image. In this case, the first-color exposed portion potential V is affected by the influence of light shielding by the toner attached to the first color and the charge of the toner itself. _L Slightly higher potential V _M Latent image is formed and DC bias V _DC And potential V _M Development according to the potential difference is performed.
[0031]
For the third color cyan and the fourth color black, an image forming process similar to that of the second color magenta is performed, and a four-color visible image is formed on the circumferential surface of the photosensitive drum 10.
[0032]
The toner supply device for controlling and supplying new color toners to the developing units 14Y, 14M, 14C, and 14K includes a plurality of detachable toner cartridges 15 (Y, M, C, and K) and a toner storage unit 16 ( Y, M, C, K) and toner conveying means 161 (Y, M, C, K).
[0033]
On the other hand, one transfer material (transfer paper or the like) P carried out from the paper feed cassette 20 via the half moon roller 21 is temporarily stopped near the position of the registration sensor via the intermediate paper feed roller pair 22A, 22B. Is fed to the transfer area by the rotation of the registration roller pair 23 of the paper feed unit.
[0034]
In the transfer area, the transfer means 17 for applying a voltage for transferring the toner image to the peripheral surface of the photosensitive drum 10 in synchronism with the transfer timing is pressed against the transfer area P, and the supplied transfer material P is sandwiched between them. Color images are transferred in a batch.
[0035]
Next, the transfer material P is neutralized by a separating means 18 such as a sawtooth electrode, separated from the peripheral surface of the photosensitive drum 10 and conveyed to the fixing device 24, and a heat roller (upper roller) 241 and a pressure roller (lower roller) 242. After the toner is welded by heating and pressurizing, the toner is discharged onto a discharge tray 26 outside the apparatus through a pair of discharge rollers 25A, 25B, and 25C. The transfer means 17 is retracted away from the peripheral surface of the photosensitive drum 10 after the transfer material P has passed, and prepares for the next toner image formation.
[0036]
On the other hand, the photosensitive drum 10 from which the transfer material P has been separated is subjected to the removal and cleaning of residual toner by the pressure contact of the blade 191 of the cleaning device 19, and is again subjected to charge removal by the PCL 12 and charging by the scorotron charger 11 to form the next image. Enter the process. The blade 191 moves immediately after cleaning the photoreceptor surface and retracts from the circumferential surface of the photoreceptor drum 10. The waste toner scraped off into the cleaning device 19 by the blade 191 is discharged by the screw 192 and then stored in a waste toner collection container (not shown).
[0037]
FIG. 2A is a perspective view showing the photosensitive drum 10 and the drive mechanism 30. FIG. 2B is a partial cross-sectional view of the photosensitive drum 10 and the drive mechanism 30.
[0038]
The drive mechanism 30 includes a drive motor (drive source) M1 such as a pulse motor and gear trains 31 to 33 connected thereto. The final gear 33 of the gear trains 31 to 33 meshes with a drive gear (drive transmission member) 34 that is provided coaxially with the photosensitive drum 10 so as to be rotatable.
[0039]
A shaft 103 is fitted to flanges (driven transmission members) 101 attached to both ends of the photosensitive drum 10. Therefore, the end surface of one flange 101 and the side surface of the drive gear 34 are located at a predetermined interval, and a connection elastic body (drive connection member) 35 provided on the drive gear 34 and a connection provided by the flange 101. The driving force of the driving motor M <b> 1 is transmitted to the photosensitive drum 10 by the projection member (driven connection member) 36.
[0040]
In the illustrated embodiment, the shaft 103 is fixedly supported with respect to the main body of the image forming apparatus, and the drive gear 34 is fitted to the shaft 103 via a bearing (not shown), for example, an oilless bearing. A flange 101 attached to 10 is fitted to a shaft 103 via a bearing 102. The shaft 103 may be rotatably supported with respect to the image forming apparatus main body, and the photosensitive drum 10 may be fixed to the shaft 103.
[0041]
FIG. 3A is a perspective view showing the photosensitive drum 10 and the connecting means.
[0042]
FIG. 3B is a front view showing the structure of one embodiment of the connecting elastic body 35.
[0043]
The connecting means comprises a drive connecting member and a driven connecting member. The drive connecting member includes an elastic member 35 having both end support beam portions (flexible beam-like portions) 351 that can be elastically deformed, and a fluid-filled type that is fixed in surface contact with one surface of the both end support beam portions 351. Anti-vibration means 37 is provided. The driven connecting member is composed of a connecting projection member 36, and the connecting projection member 36 is brought into contact with and connected to both end support beam portions 351, and the rotational driving force of the driving source M1 is composed of a driving connecting member and a driven connecting member. It is transmitted to the flange 101 of the photosensitive drum 10 through the connecting means.
The elastic member 35 that transmits drive between the drive gear 34 and the flange 101 of the photosensitive drum 10 is provided with a connecting elastic body 351 having support beam portions 351 at both ends of the drive gear 34. The support beam portion 351 is fixed in a positional relationship in which the drive gear 34 is substantially in the radial direction. On the end face of the flange 101, a rod-like and rigid connecting projection member 36 is fixed. In the assembled state, as shown in FIG. 3 (b), the connecting projection member 36 abuts substantially at the center position of both end support beam portions 351 of the connecting elastic body 35, and as the drive gear 34 rotates. The connecting projection member 36 is pushed in the direction of the arrow through the both-end support beam portions 351, and the drive transmission to the photosensitive drum 10 is performed.
[0044]
In the drive connecting member of this embodiment, a fluid-filled vibration isolating means 37 is provided on the opposite side to the contact point of the connecting projection member 36 of the both-end support beam portion 351 while making surface contact while deforming at a constant compression rate. Yes. In the present invention, both end support beam portions (first elastic members) 351 that determine the natural frequency of a drive system composed of a rotating body and a drive source by elastic deformation behavior, and the elastic behavior of both end support beam portions 351 are described. The drive transmission portion has a fluid-filled vibration isolating means (second elastic member) 37 that acts and increases its damping characteristics, which will be described in detail below.
[0045]
The coupling elastic body 35 of this embodiment is a resin molded member made of polyacetal (POM), and is firmly fixed to the drive gear 34 by, for example, three screws. The both-end support beam portion 351 is a both-end fixed both-end support beam having a thickness of 1.8 mm and a length of 35 mm, and the natural frequency is determined thereby. As the material for the connecting elastic body 35, in addition to the above, an industrial resin material or metal material having elastic properties such as ABS resin, SUS alloy, galvanized steel plate (SECC-C-20 / 20), aluminum alloy is selected. Can be used. In the embodiment, the both-end support beam portion 351 is in the form of a cantilever support beam portion 352 as shown in FIG. 3C.
[0046]
3 indicate the direction of insertion of the connecting projection member 36 into the connecting elastic body 35 and the direction of rotation of the drive gear 34 and the connecting elastic body 35.
FIG. 4 shows another embodiment of the connecting means. In the figure, parts having the same functions as those in FIG.
[0047]
As shown in the perspective view of FIG. 4A, the coupling elastic body 35 having both end support beam portions 351 is provided on the end face of the flange 101, and the both end support beam portions 351 are substantially in the radial direction of the flange 101. It is fixed in the positional relationship. The both-end support beam portion 351 is press-fitted with a fluid-filled vibration isolating means 37 in contact therewith. Further, a rod-like and rigid connecting projection member 36 is fixed to the end face of the drive gear 34. In the assembled state, as shown in FIG. 4B, the connecting projection member 36 has both end support beam portions 351. As the drive gear 34 rotates, the connecting projection member 36 pushes the both end support beam portions 351 in the direction indicated by the arrows, and the drive transmission to the photosensitive drum 10 is performed.
[0048]
5A is a cross-sectional view of the fluid-filled vibration isolating means 37, and FIG. 5B is a cross-sectional view taken along the line AA of the fluid-filled vibration-proof means 37.
[0049]
The fluid-filled vibration isolating means 37 includes a viscoelastic member 371 and a viscoelastic member 371 on the side in contact with the flexible beam-like portion (both end support beam portion 351 or cantilever support beam portion 352) of the connecting elastic body 35. And a box body 370 that is closed. A partition plate 372 having a fluid circulation orifice 372A is fixed substantially at the center in the box 370. The inside of the box 370 moves through an upper first fluid chamber 373, a lower second fluid chamber 374, a second fluid chamber 374, and a lowermost air chamber 375, which are partitioned by a partition plate 372. An anti-vibration rubber film member 376 is provided for partitioning. The first fluid chamber 373 and the second fluid chamber 374 contain a viscous fluid in a hermetically sealed manner, and the air chamber 375 is filled with air or gas.
[0050]
As the connecting elastic body 35, a resin such as polyacetal (POM) or ABS, or stainless steel (SUS), SECC, aluminum alloy or the like is used. Anti-vibration rubber member 376 of fluid-filled vibration-proof means 37 has high vibration absorption performance for ethylene propylene rubber (EPDM), silicon gel, oil-impregnated porous rubber, butyl rubber, chloroprene rubber, thermoplastic elastomer, and thermoplastic resin. Added high-performance materials are used. As the viscous fluid, silicon oil, electrorheological fluid (ER fluid), electromagnetism viscous fluid (EMR fluid) or the like is used.
[0051]
In the viscoelastic member 371 of this embodiment, high vibration absorption performance is added to chloroprene rubber (CR), ethylene propylene rubber (EPDM), silicon gel, oil-impregnated porous rubber, butyl rubber, thermoplastic elastomer, and thermoplastic resin. High functional materials are used.
[0052]
The fluid-filled vibration isolating means 37 is an elastic body having a JIS rubber hardness of 20 to 100 degrees, preferably 40 to 80 degrees. A viscoelastic body having a mechanical loss coefficient tan δ of 0.3 or more, preferably 0.5 or more, the rotating body 10 or a flywheel that rotates integrally with the rotating body 10, a coupling elastic body 35, The natural frequency of torsion, which is composed of the spring constant and damping coefficient of the drive transmission system composed of the fluid-filled vibration isolating means 37, can be controlled to 5 to 60 Hz.
[0053]
The fluid-filled vibration isolating means 37 having such characteristics is used for connecting the flexible beam-shaped portion 351 in a pre-compressed state with a compression rate of 1% to 15% as shown in FIG. The surface contact is made on the side opposite to the contact point of the protruding member 36 with a certain area.
[0054]
The inventor uses the fluid-filled vibration isolating means 37 having a JIS rubber hardness of 61 degrees for the photosensitive drum 10 having an inertia moment of 27000 gcm 2 and abuts on the back side of the flexible beam-shaped portion 351 with a compression rate of 10%. By configuring the fluid-filled vibration isolating means 37 against the flexible beam 351 having a loss coefficient tan δ of 1.9 and a torsional natural frequency of 15 Hz, the moment of inertia of the rotating body 10 is 10,000 g · cm ² ~ 30000g · cm ² As a result, the gain of the transfer coefficient can be reduced, and the optimum vibration isolation characteristics can be obtained.
[0055]
FIG. 6 is a block diagram showing an embodiment in which the rotating body driving device of the present invention is applied to belt photosensitive member driving. In the figure, parts having the same functions as those in FIG. Further, differences from the embodiment will be described.
[0056]
A driving force from the driving motor (driving source) M1 is transmitted from the gear 31 to the driving gear 34, a connecting elastic body 35 provided in the driving gear 34, a connecting protrusion member 36 integrated with the flywheel 104, and It is transmitted to the flywheel 104 through the connecting means consisting of The drive shaft 105 of the flywheel 104 is connected to the flywheel 104 but is not connected to the drive gear 34. Therefore, the drive shaft 105 and the drive gear 34 rotate as separate bodies, and the drive of the drive gear 34 is not transmitted through the drive shaft, but via the connecting means including the connecting elastic body 35 and the connecting protrusion member 36. Communicated.
[0057]
The speed unevenness transmitted to the flywheel 104 is reduced by the inertia of the connecting means and the flywheel 104, and this driving rotation is performed via a connecting member (coupling) 107 that makes the belt cartridge 106 detachable. Thus, the belt photosensitive member 110 that is transmitted to the driving roller 108 and wound between the driving roller 108 and the driven roller 109 can be driven with high accuracy by preventing vibration.
[0058]
7A is a side view of the connecting member (coupling) 107, and FIGS. 7B and 7B are cross-sectional views of the connecting member 107. FIG.
[0059]
The connecting member 107 includes a connecting joint 107A on the photoreceptor side and a connecting joint 107B on the flywheel 104 side. The connecting joint 107A is a male type having a plurality of convex portions, and the connecting joint 107B is a female type having a plurality of concave portions. The coupling joint 107A and the coupling joint 107B are fitted so that their axial directions coincide with each other, whereby the driving shaft on the photoreceptor side and the driving shaft on the flywheel 104 side are coupled.
[0060]
FIG. 8 is a characteristic diagram showing the relationship between the excitation frequency and the gain of the transfer function (vibration transmissibility indicating the ratio of the output frequency to the input frequency).
[0061]
The conventional solid type anti-vibration rubber has the characteristic that if the loss factor is increased, the resonance is suppressed, but the anti-vibration area goes in the direction of deterioration, whereas the viscous fluid, the orifice, the anti-vibration rubber member, Thus, the loss factor can be increased in the resonance region, and the loss factor can be decreased in the vibration isolation region. Therefore, ideal vibration characteristics as shown in FIG. 6 are exhibited.
[0062]
With the above configuration, the fluid-filled vibration isolating means 37 is dominated by the moment of inertia of the inertial body (drive gear, flywheel, photoconductor drum, belt photoconductor drive roller, etc.) and the elastic frequency of the torsion by the elastic member. The damping coefficient can be controlled freely and freely, and the degree of freedom in design is greatly improved. The fact that the natural frequency and damping coefficient of the photosensitive member drive system can be set freely means that, as a concrete effect, in the region of higher frequency than the natural frequency, the gain of the transfer function is inherently in the region of lowering. As a result, the unevenness of speed is reduced, and the effect of the damping member reduces the resonance level near the natural frequency due to the effect of reducing the gain of the transfer function itself. The speed unevenness can be efficiently reduced, and as a result, it is possible to obtain an effect that the photoreceptor driving accuracy is remarkably improved.
[0063]
Further, by adopting the viscoelastic member 371 of the fluid-filled vibration isolating means 37, if the resonance gain is similar to that of the conventional solid viscoelastic member, Since the gain in the vibration attenuation region is lowered, the speed unevenness is further reduced (see FIG. 8).
[0064]
Recently, a control type vibration isolator capable of actively controlling dynamic characteristics has been developed so that ideal vibration isolation characteristics can be obtained in response to changes in external force. There are a mechanical control system and a control system using an electrorheological fluid (ER fluid). The ER fluid is a fluid having a property that the viscosity changes according to the strength of the electric field when placed in an electric field, and has a feature that the reaction is reversible and the reaction time is short. An electrorheological viscous fluid (EMR fluid) is a fluid in which composite particles sensitive to an electric field and a magnetic field are dispersed in an electrically insulating solvent, and the shear stress of the EMR fluid is reduced by a synergistic effect by simultaneous application of the electric field and the magnetic field. Variable control.
[0065]
FIG. 9 is a block diagram showing another embodiment of the rotating body drive device.
[0066]
The fluid filled type vibration isolating means 37 is connected to the electric field generating means and / or the magnetic field generating means 111 and is variably controlled by the fluid control unit 112. The driving motor M1 is controlled by the motor control unit 113.
[0067]
When it is detected that the rotating body load condition of the photosensitive drum 10 or the line speed has changed, the process control unit 114 controls the fluid control unit 112 and the motor control unit 113 to control the viscosity of the ER fluid or EMR fluid. By performing variable control, it is possible to obtain optimum vibration isolation characteristics against changes in the excitation frequency and natural frequency.
[0068]
FIG. 10 is a characteristic diagram showing changes in transfer function when control is performed using ER fluid or EMR fluid.
[0069]
In a machine with two line speeds, the natural frequency and damping coefficient of the transfer function are changed by controlling the viscosity of the fluid based on the motor speed information when the line speed is changed from the motor control unit 113. And control to reduce the speed unevenness. That is, when the line speed is 1, the fluid viscosity is controlled to be small, and when the line speed is 2, the fluid viscosity is controlled to be large.
[0070]
As a result, speed unevenness near the resonance region and even high-frequency speed unevenness can be reduced efficiently, and it is stable and strong against disturbances such as vibration from the development drive unit or load fluctuations of the cleaning blade, transfer roller, etc. A drive system is obtained. Further, even when the load conditions and the line speed change, an optimum vibration isolation characteristic can be obtained, and a stable drive system can be obtained.
[0071]
FIG. 10 shows the position of the speed unevenness component accompanying the change in the transfer function and the line speed when the viscous fluid is controlled, and the transfer function is controlled so that these relationships do not resonate.
[0072]
FIG. 11A is a block diagram showing still another embodiment of the rotating body drive device, and FIG. 11B is a cross-sectional view of the fluid-filled vibration isolating means 38. In the figure, parts having the same functions as those in FIGS. 5 and 9 are denoted by the same reference numerals. Further, differences from the embodiment will be described. This is an embodiment in which control is performed by applying a fluid-filled vibration isolating means having a plurality of orifices 382A and 382B.
[0073]
A first orifice 382A and a second orifice 382B are formed in the partition plate 382 fixed in the box 370. A movable plate 381 is slidably provided on the lower surface side of the partition plate 382. The movable plate 381 has an opening 381A. The movable plate 381 is moved by the drive motor M2. When the second orifice 382B of the partition plate 382 and the opening 381A of the movable plate 381 coincide with each other, the fluid in the first fluid chamber 373 and the second fluid chamber 374 communicate with each other at this opening position. Instead of the movable plate 381, an electromagnetic on-off valve may be provided in the opening 381A. Further, the number of orifices is not limited to two, and three or more orifices can be provided.
FIG. 12 is a characteristic diagram showing changes in the transfer function when mechanical control is performed.
[0074]
In a machine with two line speeds, the natural frequency and damping coefficient of the transfer function are changed by controlling the viscosity of the fluid based on the motor speed information when the line speed is changed from the motor control unit 113. And control to reduce the speed unevenness. That is, when the line speed is 1, the fluid viscosity is controlled to be small, and when the line speed is 2, the fluid viscosity is controlled to be large.
[0075]
The main configuration is as shown in FIG. In machines with two line speeds, the natural frequency and damping coefficient of the transfer function are controlled by controlling the number of orifices based on the motor speed information when the line speed changes from the motor control unit 113. It is controlled so as to reduce the speed unevenness.
[0076]
FIG. 12 shows the position of the speed unevenness component accompanying the change of the transfer function and the change of the line speed when controlled, and the transfer function is controlled so that these relationships do not resonate. That is, when the line speed is 1, the number of orifices is controlled to 2 (382A, 382B), and when the line speed is 2, the number of orifices is controlled to 1 (382A).
[0077]
FIG. 13 is a cross-sectional configuration diagram showing another embodiment of a color image forming apparatus to which the rotating body driving device of the present invention is applied.
[0078]
In addition, about the code | symbol used in drawing, the same code | symbol is attached | subjected to the part which has the same function as FIG. Further, differences from the above embodiment will be described.
[0079]
The photosensitive drum 10 which is a drum-shaped image carrier, for example, is provided with a cylindrical transparent resin base formed by a transparent acrylic resin transparent member inside, and a transparent conductive layer and an organic photosensitive layer (OPC) are provided. It is formed on the outer periphery of the substrate and is rotated in the direction indicated by the arrow in FIG. 13 while being grounded. By providing a connecting elastic body 35 having the flexible beam-like portion 351 and a fluid-filled vibration isolating means in the driving connecting means for transmitting the driving force from the driving source to the photosensitive drum 10, the photosensitive drum is provided. 10 is driven with high accuracy.
[0080]
In the color image forming apparatus according to the present invention, a plurality of image forming units (four sets in the figure) including charging means, image exposing means, and developing means are arranged around the image carrier 10.
[0081]
11Y, 11M, 11C, and 11K are scorotron chargers (hereinafter referred to as chargers 11 (Y, M, C, and K)), which are held at a predetermined potential with respect to the above-described organic photoreceptor layer of the photoreceptor drum 10. A charging action is performed by the corona discharge by the grid and the discharge wire, and a uniform potential is applied to the photosensitive drum 10.
[0082]
13Y, 13M, 13C, and 13K are image exposure means (hereinafter referred to as exposure optical system 13 (Y, M, C, K)) that perform image exposure based on the image signal, and are arranged in the axial direction of the photosensitive drum 10. An exposure optical system composed of an arrayed LED and a self-focal lens that is an equal magnification imaging system. Each color image signal read by a separate image reading device is sequentially extracted from a memory, and each of the above-described exposure optics. The system 13 (Y, M, C, K) is input as an electric signal, and a latent image is formed by the rotation (sub-scanning) of the photosensitive drum 10. Each of the exposure optical systems 13 (Y, M, C, K) is attached to a support member 130 provided as an optical system support means, and is accommodated inside the substrate of the photosensitive drum 10.
[0083]
Reference numerals 14Y, 14M, 14C, and 14K denote developing units that store yellow (Y), magenta (M), cyan (C), and black (K) developers. A developing sleeve 140 that rotates while maintaining a gap, and a magnet roller 142 having a peeling magnetic pole.
[0084]
Each of the developing units 14 (Y, M, C, K) is charged by the charger 11 (Y, M, C, K) described above, and image exposure is performed by the exposure optical system 13 (Y, M, C, K). The electrostatic latent image formed on the photosensitive drum 10 is reversely developed in a non-contact state by applying a developing bias voltage.
[0085]
The document image is stored in the memory once as an image signal for each color of Y, M, C, and K, in an image reading device separate from the present device, and an image read by the image sensor or an image edited by a computer. Stored.
[0086]
When the image recording is started, the photosensitive drum 10 is rotated counterclockwise (arrow direction in the figure) by starting the photosensitive drum driving motor, and at the same time, application of a potential to the photosensitive drum 10 is started by the charging action of the charger 11Y. .
[0087]
After the photosensitive drum 10 is applied with an electric potential, exposure by the electric signal corresponding to the first color signal, that is, the yellow Y image signal is started in the exposure optical system 13Y, and the photosensitive layer on the surface thereof is rotated by rotating the drum. Then, an electrostatic latent image corresponding to the yellow (Y) image of the original image is formed.
[0088]
The latent image is reversely developed by the developing device 14Y with the developer on the developing sleeve 140 in a non-contact state, and a yellow (Y) toner image is formed as the photosensitive drum 10 rotates.
[0089]
Next, the photosensitive drum 10 is further applied with a potential on the yellow (Y) toner image by the charging action of the charger 11M, and corresponds to the second color signal of the exposure optical system 13M, that is, the magenta (M) image signal. The exposure is performed by the electric signal, and the magenta (M) toner image is sequentially superimposed on the yellow (Y) toner image by non-contact reversal development by the developing unit 14M.
[0090]
By the same process, the charger 11C, the exposure optical system 13C, and the developing unit 14C further generate a cyan (C) toner image corresponding to the third color signal, and the charger 11 (K), the exposure optical system 13K, and the developing unit. With 14K, a black (K) toner image corresponding to the fourth color signal is sequentially superimposed, and a color toner image is formed on the peripheral surface within one rotation of the photosensitive drum 10.
[0091]
The exposure of the organic photosensitive layer of the photosensitive drum 10 by each of these exposure optical systems is performed from the inside of the drum through a transparent substrate with respect to the exposure wavelength described above. Therefore, the exposure of the image corresponding to the second, third, and fourth color signals is performed without any influence of the previously formed toner image, and is equivalent to the image corresponding to the first color signal. An electrostatic latent image can be formed. In the developing operation by each developing device 14 (Y, M, C, K), a developing bias to which a direct current or a further alternating current is applied is applied to the developing sleeve 141, and the developing devices 14 (Y, M, C, K) is subjected to non-contact development using a one-component or two-component developer contained in K), and non-contact reversal development is performed on the photosensitive drum 10 that grounds the transparent conductive layer.
[0092]
The color toner image formed on the peripheral surface of the photosensitive drum 10 is once transferred to the peripheral surface of the intermediate transfer belt 40 provided as intermediate transfer means. The intermediate transfer belt 40 is stretched between the rollers 41, 42, 43 and the driving roller 44, and is circulated and conveyed in the clockwise direction in synchronization with the peripheral speed of the photosensitive drum 10 by the power transmitted to the driving roller 44. The
[0093]
The intermediate transfer belt 40 has a belt surface between the driving roller 44 and the roller 42 in contact with the peripheral surface of the photosensitive drum 10 and a belt surface on the outer periphery of the driving roller 44 in contact with a transfer roller 45 as a transfer member. A toner image transfer area is formed at the contact position.
[0094]
By providing the connecting elastic body 35 having the flexible beam-like portion 351 and the fluid-filled vibration isolating means in the driving connecting means for transmitting the driving force from the driving source to the driving roller 44, the photosensitive drum 10 is provided. Is driven with high accuracy.
[0095]
A color toner image composed of a plurality of colors attached to the circumferential surface of the photosensitive drum 10 is sequentially sequentially applied by applying a bias voltage having a polarity opposite to that of the toner to the roller 42 at a contact position with the intermediate transfer belt 40. It is transferred to the peripheral surface side of the intermediate transfer belt 40. That is, the color toner image on the photosensitive drum 10 is conveyed to the transfer area without being scattered by the guide of the grounded roller 41, and is applied to the intermediate transfer belt 40 side by applying a bias voltage of 1 to 2 kV to the roller 42. Transferred efficiently.
[0096]
A cleaning device 50 is in pressure contact with the photosensitive drum 10 and a cleaning device 46 is in pressure contact with the intermediate transfer belt 40, and the blades provided therein are always in pressure contact, and the remaining adhering toner is removed so that the peripheral surface is always clean. It is kept in a state.
[0097]
On the other hand, the transfer material P is carried out and fed to the timing roller 23 by the operation of the paper feed roller 22B of the paper feed cassette (not shown), and the transfer roller is synchronized with the conveyance of the color toner image on the intermediate transfer belt 40. Paper is fed to 45 transfer areas.
[0098]
The transfer roller 45 is rotated counterclockwise in synchronization with the peripheral speed of the intermediate transfer belt 40, and the fed transfer material P forms a nip portion between the transfer roller 45 and the roller 33 in a grounded state. The color toner images are sequentially transferred onto the transfer material P by applying a bias voltage which is in close contact with the color toner image on the intermediate transfer belt 40 in the transfer area and has a polarity opposite to that of the 1 to 2 kV toner to the transfer roller 45.
[0099]
The transfer material P that has received the transfer of the color toner image is de-charged, transported to the fixing device 24 via the transport plate 27, and is transported by being sandwiched and transported between the heat roller 241 and the pressure roller 242 to fuse the toner. After fixing, the paper is discharged out of the apparatus via a paper discharge roller 25A.
[0100]
By providing the photoconductive drum 10 and the driving roller 44 with the connecting elastic body 35 having the flexible beam-shaped portion 351 and the fluid-filled type vibration isolating means, the photoconductive drum 10 and the intermediate transfer belt 40 can be accurately obtained. It is driven and can stably output a high-quality color image.
[0101]
FIG. 14 is a cross-sectional configuration diagram of a color image forming apparatus using an intermediate transfer drum 60 as an image carrier. When the intermediate transfer drum 60 is used, an electrostatic latent image formed on the rotating photosensitive drum 10 is developed by a developing device 14Y including a developing sleeve 140 and a magnet roller 142, and a Y color toner is developed. An image is formed, and this Y color toner image is transferred from the photosensitive drum 10 to the intermediate transfer drum 60. Similarly, the electrostatic latent image formed on the photosensitive drum 10 is developed by the developing device 14M and M A color toner image is formed, the M color toner image is transferred from the photosensitive drum 10 to the intermediate transfer drum 60, and the C color toner image and the K color toner image are transferred from the photosensitive drum 10 to the intermediate transfer drum 60 in the same manner. Transfer sequentially. Further, the multi-color toner images (Y, M, C, K) are collectively transferred onto the transfer material P at the transfer portion where the intermediate transfer drum 60 and the transfer roller 17 are in contact with each other, and then separated by the separating means 18. The fixing device 24 fixes the image.
[0102]
Also in this color image forming apparatus, the photoconductive drum 10 and the intermediate transfer drum 60 are provided with the connecting elastic body 35 having the flexible beam-shaped portion 351 and the fluid-filled vibration isolating means, thereby the photoconductive drum 10. The intermediate transfer drum 60 is driven with high accuracy and can stably output a high-quality color image.
[0103]
FIG. 15 is a cross-sectional configuration diagram showing still another embodiment of a color image forming apparatus to which the rotating body driving device of the present invention is applied.
[0104]
As in FIG. 13, this color image forming apparatus has a charging means 11 (Y, M, C, K), an image exposure means 13 (Y, M, C, K), and a developing means around the image carrier 10. 14 (Y, M, C, K) are provided with a plurality of image forming units (four sets in the figure). However, a flexible endless belt-like photoconductor (hereinafter also referred to as a belt photoconductor) 110 is used as an image carrier, and a laser beam scanning optical device is used as an image exposure unit 14 (Y, M, C, K). Is.
[0105]
The belt photoconductor 110 is stretched around the drive roller 108 and the driven rollers 109A and 109B, is in a tension state by the action of the tension roller 116, and is in contact with the backup member 117 provided on the inner peripheral surface while being in local contact. Rotate clockwise. The backup member 117 positions the developing area of the developing sleeve 141 (Y, M, C, K) and the imaging position of the image exposure means 13 (Y, M, C, K).
[0106]
Four sets of charging means 11 (Y, M, C, K), image exposure means 13 (Y, M, C, K), and developing means 14 are provided on the outer peripheral side surface of the endless belt-shaped photoconductor 110 that is stretched. Image forming means comprising (Y, M, C, K) is provided.
[0107]
When the image recording is started, the driving motor rotates and the belt photoconductor 110 rotates clockwise through the driving roller 108, and the belt photoconductor 110 is applied to the belt photoconductor 110 by the charging action of the scorotron charger 11 (Y). Application of a potential is started. After the belt photoconductor 110 is applied with an electric potential, the image exposure means 13 (Y) starts exposure with an electrical signal corresponding to the first color signal, that is, the yellow (Y) image signal, and rotates the belt (sub-scanning). ) To form an electrostatic latent image corresponding to the yellow (Y) image of the developed image on the photosensitive layer on the surface. This latent image is reversely developed by the developer 14 (Y) on the developing sleeve 141 (Y) in a non-contact state, and the yellow (Y) toner is rotated in accordance with the rotation of the belt photoreceptor 110. An image is formed.
[0108]
Next, a potential is applied to the belt photoconductor 110 by the charging action of the scorotron charger 11 (M) on the yellow (Y) toner image, and the second color signal of the image exposure means 13 (M), that is, magenta (M ) Is exposed to an electrical signal corresponding to the image signal of (), and the magenta (M) toner image is superimposed on the yellow (Y) toner image by non-contact reversal development by the developing unit 14 (M). Formed.
[0109]
By the same process, a cyan (C) toner image corresponding to the third color signal is further obtained by the scorotron charger 11 (C), the image exposure means 13 (C), and the developing device 14 (C). (K), a black (K) toner image corresponding to the fourth color signal is sequentially superimposed by the image exposure means 13 (K) and the developing device 14 (K) and is formed within one rotation of the belt photoreceptor 110. A color toner image is formed on the peripheral surface.
[0110]
In the developing operation by the developing units 14 (Y), 14 (M), 14 (C), and 14 (K), the developing sleeves 141 (Y), 141 (M), 141 (C), and 141 (K) are respectively applied. On the other hand, a developing bias to which direct current or further alternating current is applied is applied, non-contact development is performed with a one-component or two-component developer attached on the developing sleeve 141, and the belt photoreceptor 110 with the conductive layer grounded is belted. Non-contact reversal development is performed in which toner is attached to an exposed portion on the photosensitive member from a developing sleeve 141 to which a DC bias having the same polarity as the charging of the photosensitive member 110 is applied.
[0111]
Thus, the color toner image formed on the peripheral surface of the belt photoreceptor 110 is discharged by the pre-transfer exposure device 12 after the potential of the adhering toner is made uniform by the scorotron charger 11 (F), and is transferred to the transfer portion. The toner image area on the belt photosensitive member 110 is fed from the paper feed cassettes 20 (A), 20 (B) or the manual feed unit, which is a paper feed device, conveyed to the registration roller pair 23, and driven by the registration roller pair 23. The image is transferred onto a transfer sheet fed in synchronization with the transfer roller 17 disposed opposite to the lower portion of the drive roller 108 for driving the belt photoconductor 110.
[0112]
The transfer paper that has received the transfer of the toner image is separated from the peripheral surface of the belt photoconductor 110 along the curvature of the driving roller 108, and then conveyed to the fixing device 24, where it is heated and pressed by the fixing device 24 to transfer the toner. It is fused and fixed on the paper, discharged from the fixing device 24, conveyed by a pair of paper discharge rollers 25A, 25B, and 25C, and discharged to a paper discharge tray 26 provided at the top with the toner image surface on the transfer paper as the bottom surface. The
[0113]
On the other hand, the belt photoreceptor 110 from which the transfer paper has been separated is rubbed on the surface of the belt photoreceptor 110 by the cleaning blade 191 in the cleaning device 19 to remove and clean the residual toner, thereby forming a toner image of the next document image. Continue or stop and wait. When the toner image of the next original image is subsequently formed, the pre-charge static eliminator 12 exposes the photosensitive surface of the belt photosensitive member 110 to remove the previous history.
[0114]
Also in this embodiment, the driving roller 108 is provided with the connecting elastic body 35 having the flexible beam-like portion 351 (not shown) and the fluid-filled vibration isolating means, so that the driving roller 108 can be kept constant without speed fluctuation. Can be transported at a speed of Therefore, the belt photoreceptor 110 is driven with high accuracy, can stably output a high-quality color image, and can remarkably improve the image quality.
[0115]
In addition, the rotating body driving device of the present invention is configured such that, for example, a photosensitive film is wound around a drum-shaped rotating body, and the rotating body is rotated at a uniform speed while scanning with a polygon mirror or the like. Even if it is applied to a recording apparatus that performs recording, an excellent effect can be obtained.
[0116]
According to the present invention, the natural frequency of torsion of the rotating body is dominantly controlled by the first elastic member (beam portion), and the damping coefficient is dominantly controlled by the second elastic member (viscoelastic body). And the degree of design freedom is greatly improved. The fact that the natural frequency and damping coefficient of the rotating body drive system can be set freely means that, as a specific effect, in the region where the frequency is higher than the natural frequency, the gain of the transfer function is inherently reduced. The effect of the damping member is reduced, and the gain of the transfer function itself is reduced due to the effect of the damping member, resulting in an effect that the resonance level near the natural frequency is lowered, and the speed related to the rotating body drive as a whole. It is possible to obtain an effect that unevenness is efficiently reduced and the rotating body driving accuracy is remarkably improved.
[0117]
As a result, it is possible to obtain a stable drive system that is strong against disturbances such as speed variations in the vicinity of the resonance region, vibrations from the development drive unit in the image forming apparatus, and load fluctuations such as blades and transfer rollers.
[0118]
【The invention's effect】
Since the influence of the load fluctuation and the speed variation of the drive system can be extremely reduced by the driving device of the rotating body according to the present invention, the rotating body and the photosensitive drum for forming an image can always obtain highly accurate and stable rotation. Moreover, even when the load conditions and the line speed change, the optimum vibration-proof characteristic can be obtained, so that the drive can be performed with higher accuracy than the conventional solid type (Claims 1 and 2).
[0119]
The image forming apparatus equipped with the rotating body driving device according to the present invention significantly reduces the small pitch banding, which is a major image trouble caused by the unevenness of the speed of the photosensitive member, and makes this a level that cannot be recognized by humans. It is possible to provide an image with high image quality stably (claims 7 and 8).
[Brief description of the drawings]
FIG. 1 is a cross-sectional configuration diagram of a color printer which is an example of an image forming apparatus equipped with a rotating body driving device of the present invention.
FIG. 2 is a perspective view and a partial cross-sectional view showing a photosensitive drum and a driving mechanism.
FIG. 3 is a perspective view showing a photosensitive drum and connecting means, and a front view showing a structure of a connecting elastic body.
FIG. 4 is a perspective view showing another embodiment of the photosensitive drum and connecting means and a front view showing the structure of the connecting elastic body.
FIG. 5 is a cross-sectional view of a fluid-filled vibration isolating means and a cross-sectional view taken along line AA of the fluid-filled vibration-proof means.
FIG. 6 is a configuration diagram showing an embodiment in which the rotating body driving device of the present invention is applied to belt photosensitive body driving.
FIG. 7 is a side view and a cross-sectional view of a connecting member.
FIG. 8 is a characteristic diagram showing a relationship between an excitation frequency and a gain of a transfer function.
FIG. 9 is a block diagram showing another embodiment of a rotating body drive device.
FIG. 10 is a characteristic diagram illustrating a change in transfer function when control is performed using an ER fluid or an EMR fluid.
FIG. 11 is a block diagram showing still another embodiment of a driving device for a rotating body and a cross-sectional view of a fluid filled type vibration isolating means.
FIG. 12 is a characteristic diagram showing a change in transfer function when mechanical control is performed.
FIG. 13 is a cross-sectional configuration diagram showing another embodiment of a color image forming apparatus to which the rotating body driving device of the present invention is applied.
FIG. 14 is a cross-sectional configuration diagram illustrating an embodiment of a color image forming apparatus including an intermediate transfer drum to which the rotating body driving device of the present invention is applied.
FIG. 15 is a cross-sectional configuration diagram showing an embodiment of a color image forming apparatus provided with a belt photoreceptor to which the rotating body driving device of the present invention is applied.
[Explanation of symbols]
10 Rotating body (photosensitive drum, image carrier)
101 Flange
104 flywheel
108,44 Drive roller
110 belt photoreceptor
111 Electric field generation means
112 Fluid control unit
113 Motor controller
114 Process control unit
115 Orifice controller
30 Drive mechanism
34 Drive gear (drive transmission member)
35 Elastic body for connection (elastic body member, drive connection member)
351 Both ends support beam (flexible beam)
352 Cantilever beam (flexible beam)
36 Connection projection member (driven connection member)
37,38 Fluid-filled vibration isolating means
371 Viscoelastic member
372 divider
372A, 382A, 382B Orifice
373 first fluid chamber
374 Second fluid chamber
375 Air chamber
376 Anti-vibration rubber member
381 Movable plate
381A opening
M1, M2 drive motor (drive source)

Claims (8)

Rotation having a rotating body that is rotatably supported, a driving source that drives the rotating body, a driving member that transmits the rotational driving force of the driving source to the rotating body, a driven member, and a connecting means. In the body drive device,
The connection means includes a drive connection member and a driven connection member. The drive connection member includes an elastic body member having an elastically deformable flexible beam-like portion and a surface on the one surface of the flexible beam-like portion. A fluid-filled vibration isolating means fixed in contact with each other, wherein the driven connecting member has a connecting projection member, and the connecting projection member is brought into contact with and connected to the flexible beam-shaped portion. Rotating body driving device characterized in that the rotational driving force of the driving source is transmitted to the rotating body via the connecting means. Rotation having a rotating body that is rotatably supported, a driving source that drives the rotating body, a driving member that transmits the rotational driving force of the driving source to the rotating body, a driven member, and a connecting means. In the body drive device,
The connecting means includes a driving connecting member and a driven connecting member, the driving connecting member has a connecting projection member, and the driven connecting member has an elastic member having an elastically deformable flexible beam. And a fluid-filled vibration isolating means fixed in surface contact with one surface of the flexible beam-shaped portion, and the projecting member for coupling of the drive coupling member is used as the flexible beam of the driven coupling member. A rotating body driving device, wherein the rotating body is brought into contact with each other and connected, and the rotational driving force of the driving source is transmitted to the rotating body via the connecting means. The fluid-filled vibration isolating means has a viscoelastic member on a side contacting the flexible beam-shaped portion, and a box closed by the viscoelastic member, and a fluid flow is provided in the box. A partition plate having an orifice for use, a first fluid chamber and a second fluid chamber partitioned by the partition plate, and a vibration-proof rubber film member for movably partitioning the second fluid chamber and the air chamber The rotating body driving device according to claim 1, wherein the rotating body driving device is provided. 3. The rotating body drive device according to claim 1, wherein a JIS rubber hardness of the fluid-filled vibration-proofing means is 20 degrees to 100 degrees. 3. The rotating body driving device according to claim 1, wherein a loss coefficient tan δ of the fluid-filled vibration isolating means is 0.3 or more. 3. The drive of a rotating body according to claim 1, wherein the fluid-filled vibration isolating means is in contact with the elastic body member in a compressed state with a compression rate of 1% to 15%. apparatus. An image carrier that carries at least an image; an image forming unit that forms an image on the image carrier; a drive source that drives and rotates the image carrier or a rotating body that holds the image carrier; In an image forming apparatus comprising: a driving member for transmitting a rotational driving force to the image bearing member or the rotating member; a transmitting member comprising a driven member and a connecting member;
The connection means includes a drive connection member and a driven connection member. The drive connection member or the driven connection member includes an elastic member having a flexible beam-shaped portion that can be elastically deformed, and the flexible beam-shaped portion. A fluid-filled vibration isolating means fixed in surface contact with the one surface, the fluid-filled vibration-proof means comprising a viscoelastic member on the side in contact with the flexible beam-like portion, and the viscoelasticity A box closed by a member, and in the box, a partition plate having an orifice for fluid circulation, a first fluid chamber and a second fluid chamber partitioned by the partition plate, A vibration isolating rubber film member that divides the second fluid chamber and the air chamber in a movable manner, and the fluid accommodated in the first fluid chamber and the second fluid chamber of the fluid-filled vibration isolating means is: Electrorheological fluid whose viscosity changes reversibly by turning the electric field on or off, or by applying electric and magnetic fields simultaneously An electric magnetorheological fluid shear stress of the body is changed, the load condition of the drive system, an image forming apparatus and controls so as to obtain an optimum vibration damping characteristics in response to changes in line speed. Rotating body supported rotatably, a driving source for driving the rotating body, a transmission means comprising a driving member, a driven member and a connecting means for transmitting the rotational driving force of the driving source to the rotating body; In the drive device of the rotating body having
The connection means includes a drive connection member and a driven connection member. The drive connection member or the driven connection member includes an elastic member having a flexible beam-shaped portion that can be elastically deformed, and the flexible beam-shaped portion. A fluid-filled vibration isolating means fixed in surface contact with the one surface, the fluid-filled vibration-proof means comprising a viscoelastic member on the side in contact with the flexible beam-like portion, and the viscoelasticity A box closed by a member, and a partition plate having a plurality of orifices for fluid distribution in the box, and a first fluid chamber and a second fluid chamber partitioned by the partition plate And a vibration-insulating rubber film member that divides the second fluid chamber and the air chamber in a movable manner, and a plurality of on-off valves that allow the plurality of orifices to be opened and closed, and is connected to the drive connecting member A protrusion member is fixed to the connecting member or the drive connecting member connected to the driven connecting member. The projecting member is brought into contact with and connected to the flexible beam-like portion, and the rotational driving force of the driving source is transmitted to the rotating body through a connecting means including the driving connecting member and a driven connecting member. And by opening and closing a predetermined opening and closing valve by a driving means for operating the opening and closing valve to be opened and closed and a control means for controlling the driving means, the amount of fluid flowing through the orifice can be variably controlled. An image forming apparatus characterized in that control is performed so as to obtain an optimum anti-vibration characteristic according to a load condition of a drive system and a change in line speed.

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